I m too technical but that s one of the reason why i love mechanical devices ,first fully understand their function then study their weaknesses .a dresswatch with 30m WR (even with 10) is fine ,i keep in mind and take it off before i getting close to the pool ;-),a sports watch is a different issue ,you hug your wife or children in the sea or playing with the ropes around the boat,and the pusher touched , i know it s seldom but could happen. A screwdown crown or pushers should be checked once and that s it nothing to worry about.