Casio F-91W

I have owned several F-91W (and its variant A158W) since I was 12- so that is about 3 decades of ownership.

Its a simple, battle tested watch without frills. Perfect for daily use without bells & whistles. At ¥1200 (~11 USD), even if you lose one it doesn't hurt. (I have lost my stainless steel A158 only once). The battery lasts surprisingly for about 7 years.