I have used these heaters for 3yrs now. If put up properly when not in use they wear well.
I recently purchased another one to replace the one I ran over with the quad. 😕

They do have a 3 year warranty, but I've not had to use it.

Bought two and they both quit working in about a month. Both did, so it's not an isolated incident. Save your money.

I got my tank heaters 10 years ago they still work .

Have one for a 50 gallon tank I only use in the winter when the automatic float waterers are likely to freeze. I have had no issues keeping ice out of the goat tank. Buying another for the cattle tank as well.

We bought 2 of these heaters approximately 10 years ago. We don't use them every year, but just tested both as our temps got down into the teens for a few days. Both heaters still run strong and in a 250 gal trough there was no ice in temps with a wind