I beg of you. My decision to set aside one workday a week to only draw things for myself, a day which is sacred and *cannot* be allowed to be moved, overwritten, or rescheduled by other work, has revitalized my creativity and love of art. Do it. Do it for yourself.
Seriously. I want to write original stuff a lot, but other times I also just want to work on fanfiction or other passion projects even if those might never see the light of day.
That sounds like a great idea for any creative field! A bunch of industry jobs I've looked at (I'm a biologist by training) let their employees use one day a week for their own pet projects.