I don’t remember but it wasn’t years, for me it was no issue since I kept each year in a separate box with everything orderly and easy to read, stapled and paperclipped, so all I had to do was take that box into them.
I did the same for my accountant so that all he had to do was check my figures and make sure they matched each organized stack of receipts and bills and cancelled checks, in return he didn’t charge me much.
I was asking because I’ve heard different recommendations, even from accountants, about how far back to keep records.
Currently, I’ve reached the stage of life where I’m fortunate enough to have income that is mostly from investments and SS; and the accounting software is all computerized. There can only be dispute on the deduction side, where I don’t do anything radical or expensive. My business interests closed out a couple of years ago.
Still, I remember an engineer I knew years ago who was going through a divorce and didn’t have a lot of money. He got dragged through multiple audit sessions where he thought the only goal was to get a “W” for the auditor.