Here are some tips (for not just dev tools) :

- Give a score (of interest) to your link/tool.

- Work on a good consistent hierarchy + tag-system for your DB

- Ask yourself first : Is this a popular link that I can later find easily by just googling the keyword ? if the answer is yes, don't save it. (I also sometimes append the keyword itself to my notes)

This way I mostly stopped worrying about the size of my bookmarks DB. I just add stuff. I know that I can later open the right place and sort that list by importance.

It is not perfect, and it always needs some maintenance (which I approach as a fun exploration)