almost nothing in quilting is a "must".
i used to be fanatically against prewashing. then i started buying fancier fabrics at higher prices. wouldn't you know it? the color from one of them (a red) rubbed off onto another while it was still in the drawer. another (a blue) bled like a stuck pig when i washed the finished quilt.
both of those fabrics were selling for $9 per yard in quilt shops!
in all but two cases, no fabrics shrink on me by more than "a tadbit" unless they are of the type sold in quilt shops.
so ... as crazy at it sounds ... the more i pay for a fabric, the more likely i am to prewash it.
go figure. :roll: