I have 10 I handle mine as much as I can. I try to pay more attention to the little ones. It seems though they can start off cranky, and calm down. But, I've never seen an extrememly calm snake get cranky from lack of handling. I handle more in the summer time though. I take them on pet store runs (I trust my local pet store with my life). It's a lot of fun teaching about snakes, and mine are all super sweet.

To put a number on it, little ones are probably handled 2-3 times a week. Big ones, not so much. Maybe once or twice a week. I think it's awesome that my 3 yr old neice would rather play with the snakes, than my kittens. I love it! So, I have some I handle all the time to keep them used to it for her.