The very few snakes I have that are completely on cypress or aspen get a full clean-out every 3-4 months in addition to spot cleaning the soiled areas as they appear.
I don't throw away the used bedding when I do the full clean-out, I put it on my veggie garden out back. Makes for a great mulch.
Haha, yup there's a reason all the mulch around my house is cypress
I do a full clean out about 4 times a year, spot clean everyday.