I save all my executed trades daily with commisions and exchange taxes included (Not skipping one day) I keep a seperate sheet for dividend income and also the taxes paid for it. At the end of calendar year I bring everything together on excel with income/expenditures, invoices for software,data feeds etc, then get a full report file from my broker and compare everything. I keep my own log and the brokers log on a file, of that calendar year (Physically&Digitally) and after that in case I am approached by a tax officer "Here you go eveything is here"