"Let your snake be your guide"
Aside from the mandatory "settle in" period when you first bring your snake home, and the 48 hour digestion period, let your snake tell you how much handling is too mu8ch.
I have 3 snakes. 2 of them are absolute sweethearts, that can be handled as much as I, or my daughter, want to without any undue stress or issues. It is simply a matter of not being stressed out. They are very calm and relaxed, in hand. 1 of them is still "settling in"(even after a month with me), and I am working with her on not being so "jumpy" when objects move around her, and so I handle her less often, until she settles down a little more.