As old as I am - 71. In the past 10 years, I've replaced all the plumbing, the roof, gutters, electrical, remodeled a bathroom, new outdoor deck & stairway & 2 new air conditioners.
I once owned a house in Michigan that was built in 1923. The interesting part about it was that it originally sat somewhere else and was moved to the present location, so it actually could have been older than that. 1923 was when it was moved. Our elderly neighbor was living next-door when the house was moved and said it was brought down the street on big wooden rollers and was pulled by a team of horses. Then it was jacked up and set on a basement foundation that had been built. They did a somewhat-less-then-perfect job of it, though, as it was a little bit lopper-jawed on the foundation but not enough to make a difference. There were two massive beams for the foundation, one wood and the other one iron. The original fireplace had been replaced at some point with a huge furnace in the basement, waaaay too big for the house. It kept the house nice and toasty in the Michigan winters, though. Another decorative fireplace had been built, but it wasn't a functioning one. We also had a house in Orlando that was in a historic district and was built in 1925. The present house is only about 30 years old.
Present house is 50. I would like to built a new smaller house designed with our age and disability in mind, but he says he will leave this place only in a body bag. I asked him if he had a color preference, but he hasn't replied yet.