Maybe historical vacancy rates for the market?

Of course, I'd verify everything including historical costs and income, current leases, etc before closing. 

Historically over decades nationally averages are about 10% vacancy, 50% opex, rent growth of 1 to 2% annually.So a seller touts a 6.5 cap with 4% rent growth, 35% opex, and 3% vacancy.

Tax assessors aren't always coordinated with building departments and in many cases (like here in Atlanta) the tax assessor is part of County government and the the building department is part of the City and they don't really talk.A better approach would be to research the historical building permits for the property. 

The first one is in Olde Town East which is a 3Plex new build in this Central Ohio historic district and the other one is in Delaware, OH which is a fix and flip.

Hello,I'm looking into buying a historic home, it's been very well maintained.

In our market if I can buy one for 40k and spend 40k Rehab and sell it for around 100-105k that seems to work...most are smaller homes in the Historic Areas of Tuscumbia, AL.  3 a year puts about 60k in my pocket to pay bills, live comfortably, play with grandkids, and travel.  

My wife and I own a single family home in a highly sought after Historic neighborhood in our City.

Both properties are in a good neighborhood, close to downtown, historic homes and both have been on the market for 2 years.

All of that said, the population is growing, more that one company has left San Diego for Dallas, it's more landlord friendly that California, and it's cheaper than San Diego.Now, if you were 55 and wanted to buy a second home at historically low interest rates to have someone rent and subsequently retire to, that's a different story.