Definately wait until it's quilted and bound, then wash it. Then check it over carefully. :)

I just did a quilt for my son and his fiance and glad that I went over it carefully before giving it. After washing it (and the shrinking because I used jelly rolls and didn't pre-wash), I found a couple of places where the stitching didn't catch the binding on the back side. I just sewed those places over again.

I also used two color catchers because it was black, white and red.

I always wash my quilts before they leave for their New Home. I also use a product called Soak. No rinsing and only soaking. It's expensive but I don't have to wash that many quilts. I'm a slow quilter. Or maybe it's the piecing I'm slow with. I use a color catcher and air dry. I place a clean sheet on the picnik table on the deck and lay the quilt out flat. Or across chairs, tables, whatever inside in inclement weather. I did "soak" and dry (low, in my dryer) the child's quilt that I did for Downy's Quilts for Kids. If I don't have Soak then I use something very mild, usually a cold water soak. I find that agitating a quilt isn't really necessary as they aren't really "dirty", just need some "freshening." I always include the "all cotton" and thread used and washing instructions that I like, leaving the choice up to the recipient as long as it's mild. I tend to quilt heavily so that a quilt can be "used" without falling apart. And I let them know that. Use the quilt, it isn't fragile. Baby quilts especially need to be washed and dried often. I make those to be machine washable and dryable.