If one did the tracking and found that all is well, things may be fine in the short term. But, after a time, if you don't pay attention, it's easy for items to creep up. The restaurant costs rise, as might vacations or gadgets.
Truth is, if you have a decent saving rate, say 20%, and no debt, except for the mortgage. You, you may decide to stop tracking, it's a great 'early warning' process, but if your balance sheet is heading in the right direction, I'd not criticize the decision to just enjoy that you are on the right track.