That's exactly how I do it too. It's a nicer feeling of life not always having to worry about money. Of course, you first have to be in a situation where there is enough surplus remaining.
It also works without special surpluses if you mentally separate income and expenses.
Many manage better with monthly budgets, which is perfectly legitimate.
To be honest, I simply lack the inclination and time to somehow continuously record the "other" expenses in a measurable form.