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It took me a few days to become a smoker, and a few weeks to get to the point of not wanting to smoke again (some decades later).

It took me a week or so to start having a healthier breakfast and it become part of my routine, and I've been trying to have healthier lunches for years now (and still regularly fail, normally because at lunchtimes I'm tired, stressed and yearning for comfort foods like sandwiches and snack bars).

I think anyone who believed exactly 21 days was the magic number for all habits, for all people, was grossly naive.

But what I do find is that after 21 days it's no longer novel, it's just what you do, if somebody asks you what you do about X, you no longer say "I'm trying this new thing around X, and...", you tell them your new habit. Identifying that habit as part of who you are is key to it being sticky. For some people, and for some habits, that might be true after a week, or it might take a year, but it's an important step, and if you want that habit to stick you should get to it as fast as you can.

Jan 1, 2024, I made a resolution to change my diet (basically small, very simple meals with one cheat meal a week). I'd probably made a dozen such resolutions before without much success, but for some reason this one stuck right away. I never even had trouble sticking with it, and lost a pound a week over the next 10 months. Then I met my girlfriend and we went out to eat a lot, and that broke the habit. It seems like big life changes can reset habits.

I wish I knew how I did it, because I've been unable to regain that same "this is just what I do now and it's fine" level of acceptance that seemed to be the key.

I forget what book it was, it might have been the happiness trap, but a big point they made was that building new habits and changing your life has a lot more to do with your inner notion of identity and long-run values. It's much easier to change your habits when they align with who you believe you are, The mental model difference between "I'm trying to eat healthier," and "I am a healthy eater."
> a few weeks to get to the point of not wanting to smoke again

That's a shockingly short amount of time for smoking. For me, after a few weeks I'd say some of the worst cravings had passed. But for a good year or two afterwards they'd occasionally come back, albeit briefly. I quit about 15 years ago, but given the right situation I can still feel it.

But then again, 21 days might be an optimistic number solely for the purpose of getting people started. Now we should do a study of how many people, armed with this belief, still managed to keep their habit after 21 days.
> Identifying that habit as part of who you are is key to it being sticky.

This has always been key to me. I've succeeded to identify myself as a runner, as someone who speaks French, as someone who reads books. But my identification as someone who has meaningful programming side-project, who has a garden and so on is to weak to succeed.

What is your healthier breakfast? I never really learned what is considered a healthy breakfast.
I've found that habits tied to emotion (like seeking comfort or relief) are always the hardest to rewire. It's not about willpower, it's about replacing the feeling you're chasing with something that actually works long-term.
It only takes a couple of days for a habit to stop, too. It's real easy to go from "I am a person who does this thing every day" to "I last did it half a week ago and I dunno".

(Addictions are a different story of course.)

ADHD: I can form a new habit in two or so days, but I can also lose a habit I've been doing for years within a very short time.
If I'm counting the days to form a habit, I'm not really interested in forming that habit. That's just a means to an end for me. Maybe I'm waking up earlier to have more time for myself, or I'm developing a reading habit so I can finally finish reading Hegel.

In all these cases the habit is secondary. It's all discipline and pain.

But I think there is a better relationship to be had with habits. One that isn't unfairly tied to productivity. One that I can just enjoy the struggle until I form that routine, or I build up the familiarity or the skill to do something. That kind of attention changes something fundamental about my relationship with what I'm trying to internalize and make a part of myself. It's to learn to be constantly learning and improving without making it a burden or a chore.

I happen to be taking a Team Lead course, and forming habits came up yesterday. 21 days weren't mentioned explicitly, the time frame was "a few weeks". We were given 6 criteria when forming a habit:

1. Tangible - you need to pick a tangible action that is observable. If you're trying to fix a part of your behavior you can't pick "I'll pay more attention" as a habit to correct yourself, instead you should write a note or say some phrase.

2. Up to me - don't form a habit that requires outside factors. If you want to start jogging, don't ask your neighbor to jog with you. Each time he's not available, you'll have an excuse not to jog.

3. Swallow the frog - don't push it off. This isn't a well defined criteria, the idea is to minimize excuses (like #2).

4. Daily - a habit needs to be formed by taking action every day.

5. Trigger - your action needs a trigger. This can be an internal (feeling hungry), external (a timer on your phone), or contextual (every morning, every time you walk into a conference room).

6. New - it's very hard to form a habit if you've already tried and failed. Pick an action that you haven't already tried.

There was also an important note that changing behavior often requires multiple steps. The instructor gave the example of using dental floss. It's hard to go from nothing to flossing every day, so break it into:

1. Every time you go into the bath room in the evening, pick up the dental floss, and put it down.

2. After picking up the floss becomes a habit, cut a piece of floss, and throw it out.

3. After cutting the floss becomes a habit, floss a few teeth.

And so on.

What has been most reliable for me has been instead of going from bad habit A to good habit Z, I just replace A with the easiest alternative that is less bad than A.

Obviously, this means going from A to Z can take years instead of weeks. Though, from my own personal experience and from what I see of others, trying to go too quickly from A to Z just results in whiplash and irractic behavior--where I have seen it work is when there is an existential crisis demanding that the behavior change.

I suspect there're other factors to forming habits.

Forming a running habit is probably harder than say heroin.

I also recall from the "atomic habits" book, that you can chain habits together.

The idea was that if you already have a habit of getting out of bed in the morning, you could hydrate. Just say "as soon as I get out of bed, drink a glass of water" and it is easier to form the habit.

I lost about 60lbs last year because I was officially "obese" and I wanted to be a bit healthier.

While the exact time that I formed the healthier "habit" is harder to quantify, I definitely felt like the first three weeks were the hardest. It did feel, almost overnight, by the beginning of week four it was relatively easy to keep my calorie intake lower.

Oh, that kind of habit. The good kind. It can take much less than 1 day to form a bad habit. I wonder how that asymmetry really is - were ancient humans less exposed to addictive substances and had no need to evolve a way to stop that? I have no idea what I'm talking about so, I'll end the comment here.
My theory is that we don't come from a history of plenty or safety, so, in a pre-historical sense, if something feels good that's supposed to be the signal to keep doing it because it is going to go away and you can't really get too much of it.

We were supposed to overeat because we wouldn't often get a chance. If we could be lazy and survive, then we should be lazy and preserve those calories because a time was going to come when we couldn't. It's the modern world that has all those natural predispositions screwed up. We can enjoy ourselves to excess in ways that we would never be able to in the wild, which then puts us in danger.

Maybe it's still a honeymoon thing for me but I've been trying out keto diet for few weeks and, anecdotally, now whenever I eat carbs I get a weird high. If you told me that people started farming to do it consistently, I'd believe you. Similarly, if I avoid carbs at all cost even for a day, by night I feel so bad that I must have some. Point is that as far as I can tell eating carbs is a habit/addiction as well, but much good has come from maintaining it.
IMO, getting a habit might need a "click", a resolution.

I tried many times to get into exercise, but only got into a regular schedule (daily) recently. I don't even know what happened but there is definitely a click. The number of days is not so important. Something inside just told me to do it. Same with fasting. Somehow I got into 72-hour water fast with zero preparation and "habit" a few months ago and have been doing it once or twice a month.

How to get the click is more interesting. I wish I could generate those clicks for things I want to do but not dying to do.

For me, a habit is pretty well implanted into my life after 3 months, but only after 3 years do I feel insured that it will stick for life.
In Indian culture, people do a ritual for 40 days without trying to make a habit, and my reading is that habit forming is the purpose. Sometimes what you do it not directly related to your goal, let's say fasting or going to temple or whatever, but I guess 40 days of thinking about your new-routine-adjacent-goal makes you obsess about it and try to make it happen.

So twice what is being discussed here.

It is same in Islamic culture/literature. Either one affected another or both stem from same origin.
B.J. Fogg makes this point in his book Tiny Habits. And his point *is* that you can form a habit in much less than 21 days, let alone 66.

This whole question revolves around the effort/reward ratio of a behavior. When people talk about ~21 days, they're talking about doing a hard thing until it's second nature and seems easy.

But there are other ways to make something seem easy, and there is another component in the ratio: reward. That is, even if effort stays the same, you can wire a habit by making the behavior more rewarding. (This is why people are able to get addicted to a substance after one dose -- because they can't forget the state they entered ... and it was so easy to get there.)

So the takeaway here is the you can wire habits by decreasing the amount of effort to do something that you think is good for you -- eg if you want to hydrate more, place a glass near the sink so you drink water when you get out of bed in the morning -- *and* by increasing the reward. The whole trick is getting the ratio right.

Cliche Silicon Valley example. I did an ice plunge, and it gave me a day long plunger's high. I didn't need to plunge for 21 days to get the habit. I started doing it 3 times a week after that, because I knew what I had to do to feel good.

This actually gets to something Huberman calls "duration-path-outcome". Getting clarity on what you have to do (path); how long it will take (duration); and what the payoff is (outcome), can do wonders for motivation. Confusion kills action (and for that matter, all deals, since habits are just deals we make with ourselves). If you can get clarity, reduce the effort, and increase the amount of reward and your confidence in it, I think you can get to new habits really quickly.

Fwiw, I wrote a little bit about forming habits here: https://vonnik.substack.com/p/state-changes-work-and-presenc...

I do feel the need to point out this model is far from universal.

For instance, I'm bipolar and my brain does not do effort/reward or duration. It also forgets, ignores, or refuses things no matter how much motivation I have.

I've had to find different strategies that do not rely on executive function. For example, buying a car that had a push button to start instead of a key.

It took me 3 days to fully drop sugar from coffee, at 17 I think. Never liked sweets and pastry, though, but dropping every sugar drink took me more, a couple weeks, specially Nestea.

Edit: took me 1 day to drop the remaining sugar, and plants in general.

You don’t eat plants? That’s interesting, could you share more?
Same here, I learned to not have sugar with coffee since sugar was always running out in my previous work. Not drinking coffee is not an option, so I have no choice.

And today coffee with sugar is so disgusting to me, it feels like my throat gets all sticky all of a sudden.

N=96, only followed for 84 days ... has his been replicated? How do they make claims beyond 84 days?
When I shifted to Bangalore and in March 2023, I faced water shortage (found out later it was a issue in the water supply pipes) I signed up to gym practically immediately, and used to go all days back then, just to have a bath. Hit the treadmill for 30-40 mins or lift for an hour,then have a bath. Used to gym earlier in 2022 but never got that to be a habit, but the habit stacking thing worked really well. Now that the water issues are largely sorted, I still go to the gym practically 4-5 days a week.

So that habit of gymming literally zero days. Just visited the gym, checked out the washrooms, found it acceptable, and signed up immediately.

The gym had baths?
After a lot of decades I learned the amount of time it takes to make a sea-change in character is about 10 years - providing externalities don't overly sabotage the process.

And change¹ isn't really what we do; we cover bad with good.

    We surface counterproductive drivers. 
    We counter them by layering new thinking/behaviors over old. 
    Each layer is it's own project and most don't stick for a while.
None of it is doable in 21 days, not the smallest bit.

    ¹ see also, healing
One thing about habits is that you need to make room for them. And this can mean literal room or in a metaphorical sense. If you want to eat healthy for example consider that eating healthy literally starts before you eat, when you buy groceries. If you always go shopping for groceries when you're hungry, you're not gonna buy healthy stuff, and if you don't little healthy stuff at home you won't eat healthy.
As a person who has learned a few dozen keyboard layouts, the timelines described here check out with my experience. 21 days is kind of the baseline to get to a barely acceptable typing speed, and then there’s a slow long slog as you get more and more comfortable day by day. Depending on how much you practice, it could take between 2-8 months to _really_ get comfortable with a layout.
The 21-day rule always felt a little too neat for something as messy and personal as behavior change. I’ve found that giving myself grace when I miss a day has actually helped me stick with things way longer than any rigid deadline ever did.
Regardless of that specific question, I found the book a great read.

It also has a Wikipedia article: https://en.wikipedia.org/wiki/Psycho-Cybernetics

Can you share what you learnt from it? I found it a bit woo woo but would love to change my opinion / reread it.
Trying to overcome human nature will make the process long, but aligning with it will make it fast. Good habits and bad habits are only relative—more often than not, bad habits align with human nature, while good habits are the opposite.
I think a good litmus test for a lot of behaviors is: "is this behavior serving me, or am I serving it?"
Answer: it depends. When failure to be habitual about something has significant financial cost or causes physical pain, adoption will often be nearly instantaneous.
I always wondered about the possible negative effects of having a comfortable life.

The parental love by default dictates us to create a good life for our children, which may result in too much comfort.

Do tough times indeed create stronger people? If so, how could that be incorporated into the gentleness of the modern pedagogy?

I've always heard 90 days.

However, as the article says, it really depends on what habit we are trying to establish.

Maybe a placebo, but having this 21 days target did help me start habits in .. about 3 weeks.
In the book The Invisible Game by Zoltan Andrejkovics it says 100 repetitions in esports.
it takes maybe 21 minutes to form a tiktok habit
>"If you’re trying a new diet, attempting to quit smoking or changing any daily routine, don’t expect new habits to be created in a week, or two or even three. Research suggests that the process requires 66 days (on average) and up to 8 months."

Something about the title suggested it was going to be much less than 21 days; maybe it's the domain name biasing my reading of the title.

I agree that the title implies (or even declares) that it takes fewer than 21 days. I'd argue that the articles says that it does take those 21 days, plus many more, making the title deceptive.
Trying to define any underlying logic would be to misunderstand what a habit is.
I envy the neurotypicals who can just form habits, 21 days or otherwise.

People are neurotypical rarely if ever understand what those with ADHD go through. The best description I've heard is that people with ADHD don't have habits: we have trauma.

The meaning of that is that neurotypicals have the capacity to simply go into a rom and do something. It almost passively happens. ADHD people do not. Even getting up in the morning involves 50 questions being mentally asked and answered. Do I need to take something to the bathroom? Did I run the dishwasher? Did I leave the heating on? Do I need to do laundry today? And I'm 5 seconds into my day.

A brain that seeks novelty quickly gets bored with reptition. The only way you form habits is by the trauma of the consequences of not having that habit.