Have been using these for almost 4 years. My first one lasted forever. It still worked when I threw it out due to age. Have not had a decent one since. This new one is SO SO hard to take apart and the water stream is so painful even with the blue attachment. Never had any of these problems before, though I did see someone else mention that the stream hurt their mouth. I thought they were just sensitive. The ones before this- the battery died in just a few months. That being said, it does get the teeth clean so I continue to buy it.