Yes I also am obsessed with keeping receipts, but my wife now knows why.
My shop had a break in and they stole darn near every tool I owned, going back some 40 years. Most tools were purchased in the last 10 and sure enough the insurance wanted receipts for EVERYTHING, hoping I could only come up with teh most recent.
Well, when I dropped copies of receipts doing back 10 years and adding up to 16K all he could do was pay up, and he did.
Another little trick I do at the register when I have to buy the last product that was obviously opened, I make the girl at the register sign her name verifying that the product was already tampered with. Sure enough all the parts were not in the box and the return was made simple with the register receipt from REGISTER #1.