You can wear most watches to the gym, but whether you should depends on the watch and the workout. Lifting, rowing, and anything with bar contact is harder on a watch than cardio.
What actually damages watches at the gym
- Impact: knocking a case against a barbell, rack, or bench is the main risk, scratched crystals, dinged cases, and on mechanical watches, shocked movements.
- Sweat: salt is rough on leather straps and can work into worn gaskets. Metal bracelets and leather don't love soaked sessions.
- Vibration and flex: heavy wrist-loaded lifts flex the strap and spring bars repeatedly.
Best gym choices
A quartz watch on a silicone, rubber, or NATO strap is the ideal gym setup: shock-tolerant, sweat-proof, and cheap enough that a scratch doesn't hurt. Digital watches are even better, no hands to shake loose. This is exactly the "beater" role: keep one inexpensive watch that takes the abuse so your good one doesn't have to.
When to take it off
Take a mechanical or vintage watch off for deadlifts, snatches, and anything where the bar can contact your wrist. And rinse sweat off any strap after hard sessions, especially leather, which should really stay home on gym days.
Related: What Does Shock Resistance Mean? and Is It Bad to Wear a Watch Every Day?