I have worn this watch frequently since I obtained it a couple of years ago and would definetly recommend it as an "everyday" wearer.
Needless to say if one is going to fix the inside of a car engine, etc common sense says it should be removed - just like you would do with almost any watch.
As far as waterproof, any 30+ year old LED watch should probably not be used underwater. In fact, Mike (Barbie9) says this quite clearly in his eBay item description.
Due to their age, (about 30 years old), I do not recommend to wear this watch in the shower, for swimming, etc............
As I had said before, my opinion about the Sport 3502 Mike is selling is that it is a great watch!!!