Both washing and drying can cause shrinkage.
My rule of thumb, and many others ... Abuse it to the utmost ... and know the worse case scenarios before you start sewing.
Yes, you may never intend to wash it in hot water ever again and will give it LOTS of TLC! ........ but there's always that one time that the red quilt, jumps in with your white lingerie .... and if you've done the job, you don't have to panic!!!
RE bleeders ... one hot water wash, does NOT guarantee that the bleed is over with!!
And too, I've discovered many times fabrics that bleed, that I would never have thought as potential candidates.
Similarly, there's been surprises of those that did not.