Do your shirts shrink?

Like a frightened turtle. Since our shirts are mostly made from 100% cotton (with the exception of Heather Gray, which is 90% cotton, 10% Polyester, 110% awesome), they will shrink slightly when you wash them. In our tests they gave up 5-10% after a few cycles in hot.
If you want them to shrink as little as possible, a normal routine of wash cold, dry low should be just fine. But, you already ordered a size up since you're borderline, right?