TV is a big time waster, lack of exercise kills your machine, reading expands your mind and possibilities, alcohol to excess is fattening and poisonous (I'm a big proponent of the 1-2 glass wine/day, however). 

Depending on your style, you can either be responsible for their maintenance (Typically the common expectation) or have your tenant sign something that says they will keep it running in good order and they will be responsible for maintenance to the machine.

Other than cars,   garage has fully outfitted workshop and some machine shop capability.

One would think they could just rely on word of mouth after so many years in the business but this usually isn't the case .Just like a big company like Coca Cola they have to spend big money to keep themselves relevant and keep the machine oiled so to speak .All licensed agents must work under a broker .

If I could figure out how to harness that in real life I'd be a machine!

If so put some cages around the coin machines so the crackheads don’t take crowbars to them every night lol.

And those small business's purchase equipment and machines from, more small business's.

Or own a time machine? 

@Matt Gilroy I own apartments in Indiana which are C- class cash flow machines.

Today banks are giant machines that bundle and sell billions of dollars worth of collateralized mortgages on the secondary market to hedge funds and institutional investors.