I always take my suitcase and my backpack to the airplane and then I check my suitcase at the gate. Three reasons. First, there are no baggage fees at the gate. Second, I can roll backpack on my suitcase. Third, I get to board early for "helping out". Why wouldn't you do this?

I do only check it if someone else in my party is already checking bags but that turns out to be most of the time for me.

Note: I'm actually replying to a reply that's too deep.