We have 8 of these cups. (So I don't have to wash them every night) I put them in the dishwasher and they have lasted for 5+ months now. We have one that started to leak. Like the first reply the nipple with the three slits came apart. Long story short I found you can buy the replacement tops at www.babybungalow.com/nubapr.html. They are 2.99 for two. We are very happy with the cups. We would have liked to be able to buy the replacement part more than one place. But if you think about it regular silicon nipples do not last much longer than a few months.

Randy