Rule 2 of 19 · Chapter I — Spend Less Than You Earn
Know where it actually goes
Why this rule exists
Most people can name their rent and their salary and then wave a hand at everything in between. That vague middle is where money quietly disappears: a subscription you forgot, a habit that grew, a category that doubled while you were not looking. You cannot manage a number you have never seen. Tracking is not about guilt or spreadsheets for their own sake. It is about turning a fuzzy feeling of where does it all go into a plain list you can actually do something about.
In practice
Pick one month and write down every expense, by category, without changing your behavior yet. Bank and card statements do most of the work, and you are just sorting. Look for the three biggest surprises. They are usually not the coffee, but the recurring charges and the small category that is quietly large. Then decide, once, what each category should be. You do not need to track forever. A careful look once or twice a year keeps the map honest without turning money into a second job.
When it doesn't apply
If detailed tracking makes you anxious enough to quit, do not do it. A simpler system, where you automate savings and then spend the rest freely, works fine for many people. The point is knowing your numbers, not logging every receipt for its own sake.