Be sure that you have a copy of the trust deed (reflecting your loan with the mortgagor)and those docs; be sure you have your grant deed (shows title passing from your seller)
I can't think of anything else that matters after 10 years

For the house you are in now, keep everything ... the way mortgage companies trade, bundle and sell things, you may need those things when you sell.

As for the house you sold, it's been 10 years.

Keep everything. When we applied for a home equity loan last year, , they needed to see all the escrow papers from 1981,when we first bought our house. Even tho the mortgage was completely paid off. One would think only the deed would be needed, not true. We also had to pay for a new termite inspection. Did not need a new survey, as we could find the original 1957 survey from when the house was built. So just keep everything.