With ledger, this is very easy. I also run a janky Python script which imports my various .csv files, detects which is which, and turns them into ledger entrie

With ledger, this is very easy. I also run a janky Python script which imports my various .csv files, detects which is which, and turns them into ledger entries. So a vacation stop at a gas station would look like this: 2021-01-01 Chevron Assets:Checking $-100.00 Expenses:Auto:Gas So lets say I know I spent $40 of that on food, and want to put another $40 into the vacation budget, I modify like so: 2021-01-01 Chevron Assets:Checking $-100.00 Expenses:Food $40 Expenses:Vacation $40 Expenses:Auto:Gas And it puts the rest in the gas budget. There are ways to report average expenditures and smooth them out, ways to report how many days between each purchase in a particular category or from a particular merchant, and so on. Want to amortize a particular purchase? No problem, it's a periodic transaction. ledger-cli can do accounting, really if there's a question about your money or a way you want to keep track of it, it's covered. Several graph libraries can ingest ledger files.