As long as you don't have fabrics bleeding into the whites, I don't have any trouble keeping them looking nice and fresh. Even baby quilts. I think the laundry products available today allow us to keep whites looking good, specially when you work with stable fabrics to start with.
One tip I've learned -- using a pure white batting helps keep your whites looking good. So while I like Warm and Natural for most things, I'll spring for some Warm and White or Quilters Dream when I do a quilt with lots of white.
RST
RST