That's what you will read on most watch descriptions and it's an extremely conservative value. I have never had a wrist watch battery dying on me, even after wearing it for 10 years.
Re:My “Dumb” Watch
by SamReidHughes on Thursday May 23, 2019 @10:44PM
(#19998031)
I had an MQ24, it's battery lasted 7.
According to the product description, it's more like 3 years.