You only remember where your transaction records are at the end of each year, isn't that enough to drive you crazy?

Anyway, I admit defeat in advance and usually keep three things ready: export a copy of the exchange's completed/ deposit and withdrawal records, keep a CSV of on-chain addresses / browser records, and add my own notes each time I make a large swap (what it's for, where it came from, where it's going).
I review the addresses three times like checking a checksum; otherwise, there will be a bunch of "whose is this" questions that just don't match up later.

Recently, with a bunch of new L1/L2s offering incentives to boost TVL, old users are complaining about "mining, transferring, selling," and I find it even more exhausting: cross-chain transfers, claiming airdrops, selling, then swapping back to the main chain... the transaction flow just explodes.
Honestly, don't expect last-minute adjustments at the end of the year; if you can record it on the same day, do so.
Fewer fuzzy accounts mean less self-doubt during reporting.