We might have the AC units inspected if the property was 15+ years old, make sure the water heater is less than 6 years old, that kind of thing. 

I moved in with no heat, no water, and a very poor electrical situation but by this time i was working for my mentors construction company and had an abundance of resources at my disposal.

To answer your question I've never counted, but over the many years this seems to be something that pops up, along with missing furnaces, and missing hot water heaters. 

@David C.About once a year, I post about finding some absurd amount of money inside the wall of a foreclosed house or behind a water heater in a dark basement.

Water bills are up 50% to 100%, electric bills are up 33% and gas bills are up 30%, and of course tax bills are up and new bills for new items are created. 

The tenants were out for 24 hours and came back found it and the water had already flooded out to the floor and the ceiling of 1st floor.

Our highest bidder, a downtown-based construction GC business, could not tell us what grade of lumber was quoted, would not share what brand of garage doors they used ("local vendors"), would not identify their steel beam and column supplier or water service vendor.

The Oregon Coast is ground zero for regions of the country that will in many ways become more inhabitable as temps rise, water dries and abundance of resources is more critical.

In other words, it's the jerk who doesn't give 24-hour notice to enter the apartment and who is renting out a dump with a broken hot water heater to a tenant with no background check that will have the most problems.Since you're local, you learn how to work with local tenants, property managers and contractors.

For example, an experienced plumber may suggest putting hammer arrestors on a plumbing system, to help alleviate potential water hammer problems (knocking noise) and prolong the life of components/fixtures/appliances, but the local building code may not require them.It would also depend on what you are doing the work for and how the deal #'s pencil out.