@Natalie Johnstone There's no perfect answer, but the general indicators are the simple ones - population growth, median household income growth, businesses moving to the area. 

From a guest experience perspective, in the summer months it gets hot in Pittsburgh and window units is not the best experience.I couldn't get insurance with knob-and-tube wiring, so that was required.

We had a minor flood from a 100 year rain storm that caused damage to our furnace which meant no hot water for showers to 4 units.

(i do think that household formation will slow way down in the late 2030s. 

Maybe the market is hot enough that you could still turn a profit selling as is, but typically, sellers will ask you to take care of them before closing AND likely pay less for the property simply because there are known defects.

Waynesboro has been hot for a couple years. 

I would definitely invest in a pool heating system OR get a hot tub.

The HOA bill comes with advantages for this population because it also usually comes with some amenities like a pool, hot tub, gym, etc.

Hot water is usually separated it is just the cold water that is often not.For a very large building a flat fee is the move because the back billing and tracking of who paid for what would be hectic, but for a small MF like a duplex it is very easy.I split the bill by the fractional amount of people who live in the unit.In other words, the amount of people that live in the unit divided by the total amount of people living in the builidng.So if there are 3 people upstairs and 2 people downstairs.the upstairs pays 3/5 of the bill, and downstairs pays 2/5.No need to separate anything, you know the tenants will cover 100% of the bill and this approach is fair. 

Needs some new windows in the near future but overall the previous owner had set the home up pretty well with a nice big newer bathroom, solid countertops, hot water heater and recent siding.