Da crinkly-paper "paid --- thank you" strip dat you'd be wise to hold onto for at least a day or two after your purchase, just in case you need to prove dat you weren't da one who swiped an orange-wrappered candy bar from da local convenience-store.
I've never actually been accused of shoplifting --- even just a candy bar --- but I still save my Reese-eipt for a few days after da sale --- better safe than sorry, ya know??