If you’re lucky, you’ll find one with a solid foundation with the electrical and plumbing already upgraded.
If it has the original windows, make sure someone hasn’t painted the tracks. They’re supposed to be bare wood so they can expand and contract. Also check that the sash weights haven’t fallen. If it has replacement windows, check that they were done well and don’t leak.
The house we bought was built in 1940. I’m amazed at the craftsmanship. Every door in the house is perfectly square. Every angled cut is perfect. If we maintain it, it will last forever. We were lucky and found one that had the plumbing and electrical already done. It even has a 200 amp service!