3 years is a bit short. In the last year or so, I've twice needed to find old documents -- ~5 and ~7 years old, respectively. I keep receipts for significant

3 years is a bit short. In the last year or so, I've twice needed to find old documents -- ~5 and ~7 years old, respectively. I keep receipts for significant purchases (electronics etc) in one envelope per year. It's so little space I keep these indefinitely, so if I sell an 8 year old bicycle I should still have the receipt. Everything else is in an A4 (now this comment is on-topic) file, and with so much being electronic these days it takes a decade or more to fill one up.