1. water bills2. a city of tenants who have voted tenants into positions of power, that have created laws that favor tenants to a point of ridiculousness. 3. lead paint, must eradicate immediately. a river of lawyers/tenants/city all looking to cash in on those who dont4. baltimore city and their nonsense. imagine being harassed constantly by a company of borderline imbeciles looking for anyway to squeeze money out of you all the time. buy a rental in Baltimore city and imagine no more.

Eradicating mold is incredibly expensive, plus you will have to disclose to all future buyers and renters that mold was present in the house.Another example was a 50-unit apartment complex.

Eradication can be expensive.  

I have a tenant who has been in his rental unit for 11 months of his 1-year lease and even though he keeps the place clean and pays his rent a few days late I already sent him a Notice To Vacate because he swears at my wife and threatened to sue us because we told him he owes several late charges, never paid a $400 Cleaning Fee when he moved in and because he brought roaches into his apartment and after we had a professional pest control company treat his apartment he still threatened to sue us because he says there are roaches in his apartment, but we did several thorough inspections, gave him several products to eradicate roaches and we never saw any indication that he has a roach problem.

Leasing may eradicate you having to deal with any re-arising issues the machines may go through if needed repairs are a common occurrence. 

A good exterminator should be able to identify the source and determine whether the pest infestation was caused by the tenant, or just normal pest behavior that you will need to eradicate for your renters.Most likely you are required to provide a home that is pest free, so the cost to hire an exterminator will be on you.

This eradicates the risk of him taking the deposit, then moving out without a forwarding address for any potential bills to be sent. 

I am also going to hire a professional mold company to come in and test what is left after you tried to eradicate it.

They can tear up flooring, scratch holes walls (once had a less-than-wise tenant keep his dog shut in a room - the dog scratched multiple holes in our drywall, as well as obliterated both the bedroom door and closet doors), and urinate on the floor (if it gets into the subfloor, its nearly impossible to eradicate).   

You can charge a fee or higher rent but it does not change the fact that you risk having to redo floors, eradicate urin smell, replace molding and door frames etc.