In one of her books, I think it's the Quilting for Show book, Karen McTavish shows stretching a quilt back to its original dimensions after washing.
Sometimes, depending on the quilting - washing is easier than dealing with markings individually or dealing with dissolving thread, etc. In the case of the wholecloth wall hanging I made, I measured prior to quilting, after quilting and then once it was washed, I took it from the dryer a little damp and stretched it back to the quilted dimensions.
So far, other than that I've only measured when something looked "wrong". If I laid out a top on my bed, then quilted it, washed it and it laid out differently afterward, I measure. With the labyrinth that I posted probably almost a year ago, it "shrunk" a fair bit and the borders no longer sat in the same spot on the bed. Now we have a new mattress so it looks almost like what I though it would originally.
