The problem with that is that now you're no longer tracking what you've paid to actual vendors, so you lose the ability to issue 1099's and know what you've paid who at the end of the year.  

When you have a duplex and tenants on both sides stay for ten years, it almost guarantees that something isn't right.I would study your market and determine the value of your rental, because I bet you are losing money every month.

Its when all of the work is performed and you are literally prone to lose everything. 

Meet the players. 

I know a few pro football players that had short careers.

You can earn strong appreciation but also lose a lot as the entire state becomes increasingly hostile to landlords.

Better to get what you can, than to lose it all.

This is not the best way to invest in real estate as you lose out on principal pay down but it gets you instant income that you can make mostly passive by hiring out the property management.

Logically I can't make a solid business case to cancel them, as the cash flow is fine vs losing it all with a tornado.

I guess a flat seasonal fee like any insurance policy, sometimes you win, sometimes you lose.