1) Records & exports

• Export CSVs monthly from every exchange/wallet.
• Organize by year/month: 2025/01-binance.csv, etc.
• Tag rewards/airdrops separately (income).

2) Cost basis (be consistent)

• Pick a method: FIFO or Average Cost (follow local rules).
• Document it in README-tax.txt next to your CSVs.
• If you DCA, keep a recurring buys log (date, amount, fees).

3) Wallet hygiene

• Keep used receive addresses (chain, memo/tag if needed).
• Record major bridges/swaps (hash, date, amount).
• For NFTs/staking, note the contract URL and withdrawals.

4) Common pitfalls

• Don't confuse deposit with purchase (deposit itself usually not taxable).
• Differentiate asset-to-asset trades vs crypto→fiat (often both taxable).
• Include all fees (entry/exit, network) in cost.

Minimal fields

• Datetime (UTC recommended)
• Asset / Pair (e.g., BTC/USDT)
• Qty & Price (quantity, price, currency)
• Fees (amount + currency)
• Tx hash (for on-chain)

Simple routine

• Monthly reminder to export all CSVs.
• One folder per year; subfolders per exchange/chain.
• A README-tax.txt documenting your choices (method, tools).

Values & conversions

Converter to snapshot a USD/EUR value for a specific date.

Profit calculator for quick P/L and ROI (with fees).

Organization

Reusable folder model: Tax/2025/{binance, kraken, wallets}/CSVs.

Add a mapping.txt if you rename exotic tickers.