Property managementSet aside emergency money for CAPEXEach unit has its own electric meter so the tenants will pay that on their own. 

Also they can use a moisture meter on the outside of the drywall which is huge to understand the extent of what you are dealing with.The GC in me can't help asking did you scope your sewer line? 

my main breaker only has hundred amps, but since the AC has a separate meter one guy was saying it’s OK to hook it up to the main panel though

Not sure about PA, but in NY if there are any lights in common areas the landlord needs a separate meter - you can just go count the meters on the house, if there are 5 then you know there is one for common areas.I wouldn’t use cap rates for a four unit, use comparable properties if possible.

There are some general rules but there is also room for flexibility built into the tax code depending on your specific tax strategy.Is your duplex separately metered?

You may have a shut off inside the building before the meter too which would be easier. 

Landlord can require tenants to be responsible for separately metered utilities, so can avoid waste.Landlord can get annual small increases in rent.NegativesMost of us don’t treat something we get for free the same way we treat something we’ve worked hard to obtain.S8 applicants claim “broke” and don’t like to pay application feesSame goes for security depositsS8 tenants, in our experience, tend to cause more property damage than non-S8 tenants. - Make sure you get a security deposit and perhaps do a surprise inspection of their current home.S8 requires an inspection (mostly health & safety) before approving a lease and then annually thereafter. - Not something most landlords taking care of their properties have to worry about.There are limits to clauses they allow in your lease.

Does one include heat and water versus the other that is separately metered?  

Each area has a table owners can use to calculate the deductions for utilities they do NOT want to include (or can't - like MFR with only one water meter).

The city stated they will send someone out to test the meter and yes, I charge the tenants a 5% late fee for late payments.