Personally, I throw everything in the washer (on hot) and dryer (on high) as soon as it gets home before folding it and storing it neatly on the shelf with other similar fabrics. That way, when I decide I want to use a particular fabric, I don’t have to wait while it washes and dries. Plus, nearly everything I make is washable - I assume customers are going to wash it, and that they probably won’t be using the gentle cycle. So I treat the fabric as harshly as I can when prewashing it - if it’s going to fall apart in the laundry, I’d rather it fall apart here!
But you can head on over to True Up and read up on the pros and cons of prewashing.