I completely scrub my bathroom down entirely every 7 days which lands on the weekend when I'm not at work and have the time to clean the entire bathroom.
But I scrub and clean the shower out every 3 days to prevent and get rid of any soap scum and mold in the shower.
Some people clean their showers out everyday or every other day which is good too if you have the time.
As long as you're cleaning your shower out once a week you're doing good to keep it clean and sanitary.