It may happen all at once, or gradually. You realize that at your current rate of saving, you may work well into your retirement. Or because you spend more than you earn, you are carrying credit card balances. Or perhaps you realize the need to restructure because of a life change, like marriage or divorce, or a serious illness.
On a more positive note, you just want to get to where you want to go. You want a map and a compass so you orient toward your goals for a new baby, a new home, or a long delayed vacation.
to get going.