It's unlikely that the design and layout of a house will remain up-to-date over 50+ years. People's expectations change, see for example the role of a kitchen i

It's unlikely that the design and layout of a house will remain up-to-date over 50+ years. People's expectations change, see for example the role of a kitchen in a house. 50 years ago, the kitchen was were the wife cooked. Now kitchens are open, connected to the other living spaces, and very much the central point in the house. Re-doing the plumbing is one thing, dealing with that sort of changes is another.