Purchasing old houses: do you run into

Hey guys!

I am currently researching Kentucky (Louisville, Lexington, etc) market to purchase a property out of state, and I come across lots of houses that are 100 years old!!! Apart from those old houses being absolutely adorable, I gotta think if this is a good investment... Every property has its own life span, so I am concerned with having lots of issues with old homes even with renovations... What was your experience of dealing with old homes? Also, what questions should I be asking when reviewing them? Like updated electrical, plumbing, etc?

Thank you,
Edita