Yes, they can be costly to repair or replace, however the systems do last a long time and as long as you are providing routine maintenance to it, you should be fine. 

I didn't do much else other than routine maintenance. 

(that’s not going to raise eyebrows)The easiest way to avoid this mess?

Would that raise IRS eyebrows?

Another rule of thumb would be 1% to 3% of the property’s value per year, with a floor of at least $3,000.Keep in mind that this would be for routine maintenance only.

It is a new property, less than 6 months old, so don't expect many routine repairs to start.

Here in PA. its a long drawn out Judicial process, routinely taking at least a year, sometimes much longer. 

FSBO also means the buyers agent will have to do more work as you don't have access to or the support of an office and the "usual" forms that they will want to use to ensure they stay in compliance with the local MLS and Realtor assoc.we had this experience when a buyer brought their commercial RE agent as their rep and was basically clueless of the usual routines, forms, and bench marks.

If guests are staying 3-6 months on average - adding it in as part of your cleaning routine may be the easiest way to do it.

If you're going the umbrella insurance route, perhaps see if it will cover you for several things including just the routine slip and fall (like mold or earthquake).