I was told to save all the receipts for all the building we have done, as proof of cost of building.
Being a 4th generation packrat from both sides of the family, I have a LOT of family stuff. But when I did the first ever paper purge several years ago, it went back to 1977 and filled the back of the pickup truck. I've tried to stay more on top of it, but was glad last year I had the records for the solar going back to 2013. I really needed some to 2011 though...sigh...
One of my worst nightmares is ever having to move from here...