Don't they just close up on their own?
It actually depends on a number of things, such as the amount of time waited in between stretches. If you do it to quickly as in within a few weeks the scar tissue will cause the ear no not shrink back, which is why I waited several months in between for the ear to fully heal. The jewlry also makes a difference, large hoops weigh the ear down causing it to stretch more where as plugs don't weigh it down and work simply as a spacer. How large you stretch to also makes a difference.