The idea of writing technical documentation for your home seems like excellent advise. I think many people do this in an informal manner. I'm not sure a full blown mkdoc setup is necessary -- of having your "home repair/maintenance" notes in their own subfolder of an Obsidian vault or git repository might be sufficient. In my own experience, having quick access to this info has made troubleshooting easier a number of times recently during some repairs and renovations.
I keep it in a Google Doc that I print out and have visible on the kitchen counter when I go to sell.
Even putting aside the practical value it could provide to the new homeowner, it shows the house has been well-maintained to the potential buyer. It also conveys that there are likely fewer "unknowns" about the house because it implies nothing is being hidden.
