One of my screws loosens often. Last time I went to Cartier SA explained to me that I didn't screw the bracelet the right way. She said somebody else has to do it not me. When she thightened that screw it didn't get loose for a very long time. It's happening again but I don't see that as a problem.Thanks for the feedback! The Nike one that I got is pretty tight fitting. I think I'll try boxing once and see how it goes then based on your feedback. Yours doesn't have problems with loosening screws over time, right?