I have had 2 in the past, and they both stopped working after a year or two. Can anyone recommend a thermometer that has lasted more than 3 years and has the option to add multiple sensors?

I have several LaCrosse units that have been working for many years.

I prefer the ones with so called "atomic" clocks.

I have a couple of projection units for the bedroom. One for indoor and one for outdoor. I had a unit that switched from indoor to outdoor every 5 seconds, but it was annoying to read in the middle of the night:)

Some of the newer units have color displays, but then you must have them plugged in.

I usually use lithium (not li-on) batteries in the remotes. They perform better in cold weather.