I used to keep all receipts and enter them to a bookkeeping programme on the Internet.
Hooray, after 30 years of doing this, I have finally stopped - could not get out of the habit till I recently bought a new computer and did not have anyone to transfer the programme and details to my new computer (I kept the old one just in case I felt that need to enter it all!).
So now I throw receipts out unless they are receipts that double as a warranty. I also no longer need receipts for tax purposes.....
Oh yes. We keep every receipt and record EVERYTHING for tax purposes. Any money we can keep in our pocket, instead of giving it to the taxman, is worth every cent. It is important to get some money back your tax and by being honest, and using every perk you can, why shouldn't you keep your hard earned money.
I keep receipts for major purchases for warranty purposes and any tax receipts if needed. A couple of years ago one of my grandchildren wanted a warranty for school project and of course I found heaps, some over 40 years old, so suffice to say I was pretty popular for that project.