The plumber will likely have to cut open the ceiling to confirm and make repairs, so you can save a little money by learning how to do that yourself, confirm the problem, and then call the plumber for repair, then patch the ceiling yourself.As Jonathan is trying to point out, it's important to expect these things and have funds on hand to deal with them.

As mentioned elsewhere, breakeven on cash flow is not the same as break even for taxes.Let's make some assumptions:Rental income = $1000Mortgage payment = $400 - but $300 is interest and $100 is principalOther expenses (repairs, advertising, utilities, etc) = $600Depreciation = $250The above scenario creates a break even from a cash flow perspective, however the tax scenario looks like this:Rental income minus the mortgage interest (principal is not deductible) minus the other expenses minus depreciation looks like this:1000-300-600-250 = $150 LossIf your income is over $150,000, then you cannot deduct that loss, but you can roll it over to future years. 

Consider FHA loans for lower down payments and reserve for repairs or upgrades.

They're fine for buying a turnkey, older home that gets "spruced up" and comes with a 1-year warranty on their repairs.

You might hit a few bumps in the road...tenants who imagine due dates are more like suggestions, or unexpected repairs that crop up at the worst possible moment...but that’s part of the ride.

I am just looking for insight from local MA realtors, attorneys or landlords regarding what my typical monthly expenses (if any) will likely be (I don’t mean one-off expenses like roof repairs). 

I have just over $200K left of owner-financing, but I'd like to obtain a cash-out mortgage/loan of $500K (ideally) to be able to pay off the previous owner and make some repairs, etc. 

Getting seller to do repairs. 

However, the risk of significant repairs is not to be taken lightly. 

I got a very good price on the building (about $25k per door), but it was a ton of work as in addition to tenant issues, there was TONS of physical distress (foundation repairs, sewer line and water line repairs, electrical upgrades, new roof, and apartment renovations needed for all units).