Funny thing I found out about this recently - my country has a tax model where very small businesses (defined by revenue < threshold) only pays a small flat tax - comes down to a few %. You cross that threshold and you're in the standard tax brackets which is a big jump + regular accounting, etc.

So this forced me to settle for a number at which I'm happy with my income and I can have a clear goal for that year - once that is achieved other things come in to play.

This seems basic and maybe it's just me but I never really had an idea of what I wanted to make, what is "enough" - I would just say yes to any opportunity that came my way which paid more and kept plowing forward - but there is a limit to how much you can do and it's hard to guess it before you reach it so I ended up pulling all nighters and working through weekends more than once. Now that I have my limit it's actually pretty easy to reach with ~210 regular work days according to my current rates for a really easygoing client - this leaves me with plenty of time for other stuff - if I find a better paying client I just work less for that year - I like this model.