Each of our snakes probably only gets out to sit with us for an extended amount of time once a month or longer (more frequently in the summer when we take them for local outreaches/educational events), the bigger girls rarely get handled during breeding season, and everyone else gets 'looked over' (as in actually picked up and moved around, rather than just glanced at) once or twice a week during cleaning/general maintenance. We very rarely handle hatchlings unless they are immediately great eaters, as they seem a bit more relaxed/secure when left alone.
Interestingly, our nicest/most docile snakes are the ones who get handled least (I am constantly prodding the enchi, because he keeps getting prettier as he grows, and he is a little snot). I don't really think this is related to frequency of handling though, it seems to be more of a combination of age/comfort level, and individual personality/behavior.
All in all, I don't think BPs mind one bit if you never handle them, and none of ours, anyway, have shown any increased fear or defensive behavior when taken out, if they haven't been handled in a while. They are a docile enough snake that if handled appropriately when you do get them out, they seem pretty content to just go with the flow.