You know that saying "Even a blind squirrel occasionally finds a nut"?

Occasionally we've had to fix minor items after tenants have moved in, but in general this has been working well for us.   

No extra charge for the maintenance calls (the monthly fee should cover the handling of the occasional calls)No extra charge for the renewal (the monthly fee should cover the handling of the occasional calls)Use self-showing technology to offer low-price ($300?)

We use VRBO as the main advertising source, along with the occasional FB Marketplace or Craigslist ad.

If it's the latter they can steal be a positive light in your endeavors and talk to you and occasionally take a look at seeing what you are doing.

Occasionally I would see an abandoned house come up for sale there and thought to myself it would be such a great place to drive an improving neighborhood but this was pre-investor Dave and thought that was only something companies or the wealthy did. 

There is an occasional thread on BP where the vendor has a system crash of technical glitch and transfers are delayed.

We have our on-site cleaners, and then a floater who functions as backup for the occasional mess, and to haul laundry which is taken care of off-site, then bundled back up and bagged, to be picked up early in the day before the next turnover.

Otherwise, anything else good that wears in such a way that you can reapply occasionally without full stripping is going to require a buffer. 

We do get hail storms and significant hail storms occasionally, just about as often as CA gets fires, mudslides, and fires.