I have had this vintage Wyler for many years.  I have never had it serviced. I have never had the back off  of it and don't even know how to do so.   I have worn it from time to time over the years simply because I like it's no nonsense classic look. The watch has always worked perfect and still does.  Now I'm about 80 years old and have more use for the money than I have for all the now classic watches I have accumulated over the decades.I find myself needing to sell them off.   Check back in my store as I list all my vintage watches.