I'm really ruthless about what I keep on file because my experience is that putting more stuff in the filing system doesn't mean better access to individual pieces of data. My DH is a low-level hoarder, and would keep everything - every pay stub, every bank statement, every credit card statement, every bill and receipt. The one time we did have trouble with the IRS, it took hours to find the paperwork on his stock options and the mortgage (he bought the house before he met me). I would rather have a filing system that consists of the tax returns (and associated backup - I keep info on deductions in the same file as the return), the stock info, and the mortgage.
Yes, that means I might need to pay retrieval fees to the bank or the credit card company in the event of an audit. When we had files with *everything*, we couldn't find *anything*, and if they'd cared about seeing individual bank statements, we'd have had to pay retrieval fees anyway.
If you have the space and the time and the discipline to keep a filing system going and tidy, sure, keep it all! But I don't, and I think it's better to be systematic about what stays and what goes.
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