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.....