I have two of these. They don't have the great battery life that many of my other sensors have (I've got quite a mix), but they are good enough. Maybe yours are on the old firmware? I used to have one on the old firmware, but was able to get it to update with a Wink hub. Leaksmart said they could not do it with their hub and mailing it back to them was the only option (this was years ago though). I find these quite reliable sensors, and I like the temperature reading, light and sound features that not every leak sensor gives you. Mine show firmware 113B-07D1-00000034 in my HE hub.
For low cost and reliable leak sensors, I like the Third Reality leak sensors. They are very sensitive but have sound, no temperture reading or light, and they aren't waterproof. If they get submerged, they may not work again. However, they're not expensive to replace.
If you have a lot of Leaksmart sensors, I would try to upgrade their firmware if it's not already up-to-date. And if they are running the latest firmware, then I would look more closely at why they're dropping. Maybe you have a bad repeater on the network? 
