Most of the time warranties are not used, and even when applicable, you might not find the receipt.
When you get a product with a warranty, write the expiration date on the receipt and put in a file dated with the year of expiry. Shorter 30 & 60 day files could also be created, but for most things I don't even bother.
You can now easily dispose of expired warranties with little to no thought, which is good because this is the most common case.
If you need to use the warranty, just look through them, there likely won't be that many.