The only thing I've ever had to do was swap batteries, clean the contacts and blow out the debris, if any. Reset the movement, depending on the watch. The reason I ask, is my 5y23 diver is acting up after I swapped the battery. I seems to be O/K now, but the second hand was getting hung up and would sit there and twitch for a little before running again. Does it need to be oiled? If so, where are the lube points? Thanks in advance.