Consider keeping a small basket where you fold laundry for unmatched socks. The next time you do laundry it is likely that you will find the other sock of the pair and know right where to find the match! When your basket gets full, bid farewell to the loners, knowing that the majority of the matches for the socks in the basket have been lost for some time and are likely never to be found.
Consider having 2 folders for your manuals, one for household equipment that stays with the house and one for equipment that goes with you. When the time comes to sell your house, you will be able to leave all the appropriate manuals for the new owners.