Now some say that this is an urban myth but I have worn watches for the last 60 years and never had any problems until I started TIG welding. A new Seiko automatic started losing time and died not long after I learned to TIG weld. I replaced that with a robust Seiko divers watch of the sort that used to last many years when I was a commercial diver but that too died after one year. When I took it in for repair they said that the whole movement needed replacing. Somewhat pi***d off with all this I reverted to a dirt cheap 20€ casio which worked perfectly while we were moving houses and I had not got a workshop. Then within hours of dusting of my TIG welder and doing some 5 minutes of welding it died. Coincidence? Seems too much for me so I'm going to leave my next watch in the house when I weld. As a radio amateur I know that any sort of an arc can create RF frequecies and perhaps there is some part in a watch that can act as an antenna and convert that RF to a small current but one that is strong enough to zap the delicate circuitry of a modern watch. Sorry about rambling on but it might save someone a big expense if I am correct.