Well, I prewash with hot water and dry in the hottest dryer so whatever someone does to it later it will withstand without further shrinkage. I soak fabric in vinegar or salt if I am concerned it might bleed. I get a lot of fabric from the church pantry to make charity quilts and don't want those folks to receive a gift and it not stand up to washing. I cut the corners of the fabric so I know I washed it. Usually wash it as soon as I bring it home (but not always). Do not wash FQs.