Personally I feel 100 dives a year is quite a good amout especially for recreational diving, obviously not for commericial. Looking into it, the $40 dollars or so you pay for labor isn't all that much. If you can find the tools, parts especially it's worth it but it seems like a lot of work to go to unless you are planning on going into business. Ace I'm sure you know but your arent' going to be able to find any sort of insurance unless you are qualified.