I buy stuff with debit card linked to my bank account. My bank website lets me download a CSV dump of all transactions in the account in a given timespan (it automatically sets it to after the last time I did the download). I have a script to sanitize the CSV and a hledger ruleset that parses the CSV entries to hledger log and tags common receiver names like grocery stores or utility bill companies with the appropriate spending categories.

Work needed from me: Downloading the CSV once or twice a year, running the script, checking the output for anything that didn't get tagged by the existing rules and needs extra annotation.