I was given a 1960's Seamaster by a friend. (Thanks to the great advice from the forum's members, I decided to keep it.) The watch runs great, but I know it hasn't been service in 30 years. My question is, as long as the watch is running fine, should I still have it serviced? (There are some scratches on the crystal, which drive me crazy.) Also, can you recommend any online places to have it serviced? About how much would it cost? Thanks everyone! Ethan