Sorry if this thread was made before, I couldn't find one.
I've started to prewash my fabric before I cut out any pattern pieces, to prevent shrinking. However, I keep getting different advice about how to treat denim - some say it shrinks like mad, so I should wash it at least three times before I do anything with it; others say one time is enough, others say it's not required at all. I also hear the type of denim determines how you should treat it, but in that case I can't figure out what type mine is. The fabric store can't answer me, either.
Any tips on how I should prewash it, if at all? I know the "not above 40 degrees" rule, but I'm lost on everything else. How many times should I wash it?