Comment by koolba

> But there are quite many people who have no idea how much they are spending, or sometimes even how much they are spending.

Step one would be teaching people to write down the balance of all their accounts on 12/31 of each year. Checking, savings, brokerage, and all credit card debt (including current month spending). The difference in that number over two years is your net for the year.

Your gross is going to be approximately what you report on your taxes. In reality it’ll be a bit more but this gives you an upper bound.