Which, again, is something that often isn't allowed in skill checks. How many times do you let your players attempt to pick the same lock?
Personally I kind of allow it twice. First time they open it in a few seconds if they didn't completely blow it they can still open it but it's going to take a while. Of course that's a house rule.
But as always picking the lock will either mean something relatively inconsequential such as they miss out on some treasure or they have to try a different option. There are many ways to make "nothing happens" interesting.