I saved my receipts for YEARS but I was doing some cleaning one day and thought I wouldn't need the receipts anymore. It was 7 years since I even looked at them, when the card was canceled.
Out of the blue, just by coincidence, that credit card company called me and told me I owed them 20 grand.
They knew damn well, after 7 years, the documents would be gone.
If I had just waited a couple more days, I wouldn't have needed to pay 20 grand. I could have contested it.
Just think before throwing away important documents, old or not.