What do others here do as far as keeping records...do you rely entirely on the brokerage then or keep more detailed trade history? When I start thinking about things like dividend reinvestments I wonder if I'm keeping too much data.
The latter is one reason I didn't used to keep anything in a taxable account that reinvests dividends. I still don't have individual stocks do that, to avoid record keeping hassle. Also, when I sell something, like a mutual fund, I tend to sell the whole lot to avoid having to track individual shares. That will become more of an issue after I FIRE, but I'll have more time to set up a better tracking system too.
I do keep all my brokerage statements forever, on paper, because I've run into issues with more than one brokerage where if I needed an OLD record (say, from 10 years ago) it can be a pain to get because they don't keep them on their web site that long. We also had issues with my FIL's account after he passed away where we needed cost basis info for a stock from several years earlier, but he had transferred that account to another brokerage and the original one wouldn't do any digging unless we gave them exact info about buy and sell dates. If we had that, we wouldn't need them.
If you were willing to put all that information in electronic form, though, I strongly suspect you could get through an audit without needing paper backup. You are only required to keep records going 3 years back, in general, so they can't find legal fault with that. They aren't likely to complain if the transactions are from a real brokerage that keeps records, they can always check it with them if they have to. Their bigger concern is likely to be things like dodgy "business deductions" and such.
