Not if your are exhausted after work or if your working hours prevent you from attending courses, for example night shifts leaving you tired at the morning. Try doing warehouse job for a week, see how much willpower you will have left.

Also time is sometimes convertible to money, esp. if you have children. You don't have much time left if you have to work long hours, but if you can pay someone to do cleaning, etc.for you, then you are directly buying time.