I'm afraid I'm a bit OCD about my finances (maybe because I work in accounts, and I don't earn a lot either!). I always take receipts, always check them ( and mistakes are not unknown), and always enter my expenses on a monthly spreadsheet. If I don't, I can't keep track of how much I have in my account in the latter half of the month, as there are also a few direct debits which are not always the same amount, and I do not want to go overdrawn. But it surprised me how far down the thread I got before anyone mentioned shoplifting! Now that we can carry goods out of the shop without a bag, who on earth wants to be in the position of being stopped and not immediately being able to prove you have paid?! Also, regarding emailed receipts, I hate them for two reasons 1) once they have your email address you get bombarded with their ads , in my experience, and 2) I once bought an ipad in an Apple shop and they said they'd email my receipt, but it turned out they'd input a spelling mistake and I never got it. Even if it hadn't been faulty (it was!), I like to keep receipts for large items to prove purchase and being under warranty etc.