In the contract, state that if usage exceeds 120% of the average, the guest will be responsible for the extra cost.

We are just not sure if it is deserved to keep and rent it out.

Pay extra attention to the last paragraph, rev on a first year listing will be lower, it will get better. 

It may sound nice to pay a 6% management fee but the extra fees can add up to be more than the other company that charges 10% with no additional fees.

He told me that he had found it much more useful to save the extra money for repairs, emergencies, or future investment.

People like that extra space.

My view is that the extra income from STRs/MTRs basically compensates for the extra effort.  

Buyers if you want an extra advantage over other buyers call your favorite Mortgage Banker and ask for a "Fully Underwritten" approval not just a Pre-approval.

The reality is the opposite - if it's not in writing then the PMC doesn't have to provide the service or can charge extra for it!

This but taking it a step extra: If you own a business in an S corp, having a C corp as a management company to do solo 401k and hold cash for any retained earnings needs can be a perfect addition to those who have SBA debt and want to pay it off quickly.