I do unless the piece is a wall hanging that will probably never be laundered and needs to be perfectly flat. Not only do I want to get all the dust and stuff (cat hair) off the finished quilt, I like the look and feel of a quilt once it has been laundered and allowed to find it's own degree of shrinkage. I experiment a lot with different types of batting so I get a few surprises but I've never been really unhappy with a washed quilt.