I have used these moonhoppers for over 10 years in my pe classes. They tend to last at least 2 to 3 years before breaking. I have kids from k-8th grade using them year round, not just for a specific unit. The main way for them to break is if the kids stand on the wrong side of the board for too long or jump on the wrong side too many times (or if they are over the 150 lb limit). I really like them. The only draw back is if they do get stood on the wrong side, the ring may come off it is really hard to get it back on since the ball part doesn't deflate very well. They are a lot of fun and can be combined with a jumprope for more challenges, or a hula hoop, or even dribbling a basketball while jumping- all great for coordination skills.