4 Months and 3 Broken Vibrators. Looking for Suggestions

About four months ago I bought my SO her first vibrator. It was a cheap bullet vibrator from Spencers, however it performed great up until one day when it just buzzed out and wouldn't turn back on.

After that, I got a small "body wand" for her at an adult store, which also broke after about a month of use. Once again, just up and stopped buzzing one day. The same thing happened with another bullet vibrator I got from the same store, and although it seemed like good quality (10 preset patterns, waterproof, good material, etc...) after about a month of use the cord seemed to have some damage and it would only work if it was held in a certain way.

The vibrators are only used during sex, and it's typically with my SO laying on her stomach using the vibrator on herself while I'm doing things from behind. I'm pretty sure she mostly just holds the vibrator still, right on her clit, so I don't think it's really being used too roughly, but who knows.

If anyone has any insight as to why these vibrators keep breaking or some suggestions on good vibrators to use during sex, I'd really appreciate it. I'm considering the We-Vibe.