Most "average" used care buyers don't even ask about maintenance records. If they do, a good trail of records, even without receipts usually suffices. Commercial users are more picky about wanting to see maintenance records, but I have never heard of one want to pour thru actual receipts that show it. I haven't kept actual receipts stored for years. I do keep maintenance records though. Even easier now that many OEM's have owners areas on their site where the owner can keep records of oil changes and other work done.
I get my oil in bulk from my commercial supplier. Keeping receipts around on that for a car in my garage is not going to happen. I even get my oil filters and stuff in bulk from a commercial source. I just keep a record of what I did, what I used, etc. Never had a OEM shop, commercial or personal, ever ask about basic maintenance, let alone want to see receipts. The motivation to want to keep piles of receipts for stuff like simple oil changes and such seem primarily motived by an enlarged paranoia gland.