BiggerPockets

There are a lot of answers to your question. Most all of them can be summed up with, "It depends".

If the property is located in a "Historic District' you should beware. Some of these appointed officials can be notoriously difficult to deal with.

Then there are repairs and/or rehab. You'll be dealing with plaster walls, ball and tube wiring, decrepit plumbing, no insulation, and how does it heat and cool? Oh, ha ha, I forgot good old asbestos around the pipes! Plus, back then, wood really measured an actual inch, or whatever, as opposed to today, making carpentry more challenging. Did I mention lead paint?

Renters can be hard on such properties, but then again, these properties have withstood the test of time. I've got a lovely old 20s-era upstairs/downstairs apartment in a low income neighborhood, and it just breaks my heart every time I evict someone and see how they've trashed the place. I've also got a lovely old 30's-era craftsman bungalow in a college rental neighborhood, and those little college b*st*rds can trash a place with the best of them.

Look, if I could just buy 10-year-old homes for a huge discount I'd do it all day long. But that's not where I typically find deals.

It's all about the numbers really, and having a good team that can handle whatever challenges come up, or warn you to run beforehand.

I'd take a good look at each building and make your decisions on a case by case basis. I've seen some lovely 19th century homes that have already had a lot of work done on them (so safe wiring, no asbestos, etc), but I've also seen some horrid Victorian bungalows that would cost far too much to get to a liveable standard.

If you can take the time to check things out for yourself, you may find some great deals.