I don't know what the best answer to this is, but here's what I do:
Eat more when I'm lifting heavy.
Eat less when I'm not.
I don't get into calorie counting or nutrient counting or whatever. I did for a while, and I got pretty lean, but it was also time consuming and I found it difficult to eat-to-win. If I lift heavy, I try to eat more than I normally would; if I do conditioning, I try to eat as I normally would; if I don't do anything, I eat less.
Beyond that, I don't bother with worrying about it unless I have a specific goal (pre-beach or get big or whatever). I tried worrying about it, and it really just made me miserable. Since then, I've found that if I get big in ways I don't like, I just eat less until I'm where I want to be.