What happens if I'm overcharged at checkout and don't notice until later?

If you catch it within a reasonable window - usually days or weeks depending on the store - you've got a solid shot at getting your money back, especially if you have the receipt! The trickier part is when it's been months and the store claims they can't match the transaction anymore, but honestly pushing back with your card statement usually gets results.

You're usually fine as long as you catch it and go back with your receipt before too long - stores know it happens and most will correct it without fuss. The thing people don't always realize is that some chains are stricter about timing than others, and a few will straight-up refuse if it's been more than a week or so. Keep your receipts for at least a couple weeks, and if you spot the overcharge, don't overthink it - just head back and show them the numbers. Getting grumpy about it won't help, but being straightforward almost always does.