@Vanessa Leeper Jones Every state has different codes and laws but in the State of Indiana a landlord has no liability for loss or damage to a tenant’s personal property if the tenant’s personal property has been abandoned.Because they're unresponsive they are giving up rights for personal belongs.

HOWEVER, in the meantime, said guest can come and just damage non-visiting units freely and I just have to watch?

If this has any possibility of hitting the house or doing any property damage then hire a lic/insured company and they will likely not give a discount for firewood. 

Note, even if insurance pays for all the damage your property suffers, you still lose.

Most of these issues should be addressed in your lease.Second question is what does state law allow you to collect to mitigate your damages? 

It’s not uncommon for stucco to crack a little, especially if stucco is added on top of something else like wood or block. 

My experience has been that the owner of the car would have car insurance that would cover the damage.

Budget for furniture to be damaged as well.

Roof/hvac ageWeather conditions/damage/snow removal/landscaping/salt waterSiding/roof materials (cedar vs stucco, asphalt or rolled versus tile.)Landlord/tenant friendly state  And, as you pointed out, property price. you want to lose money?

Better grade neighborhoods are going to have much tighter margins but you will not deal with as much tenant turnover or damage to your units (in general of course).