We had mice! We tried humane traps, but the mice just took the peanut butter: we tried poison, the mice didn't eat it: we tried ordinary mousetraps and eventually got one mouse... The we bought this plug-in Vermatik mouse Repeller. This was back in August. I didn't think it would work, which was why we bought a reasonably priced gadget - but - guess what? No mice since then!
The only thing I don't like about this Repeller is that it has a very bright blue light which is on all the time it is dark. This doesn't really matter as no-one sleeps in the kitchen where it is plugged in. It has an Air Purifier, but I don't notice any difference in the air quality, but that's not what it was bought for.
Worth buying to deter mice.