Depends on the snake.
JCP -> Mist daily up to about 75% and then it settles down to 40% or so then I mist the next day. Close to shed, I mist twice a day.
GBK -> Neither, she likes it dry even near shedding. 40% or whatever the ambient humidity is.
BRB -> Damp humid hide, daily misting, tightly sealed enclosure. Ambient humidity is 95% or so. She's a neonate though, so low humidity is potentially fatal.