I think that most people fail at the exercise "Routine" because they fail to realize that without lifestyle changes and a change in viewpoint, exercise is exercise for the sake of doing it and they fail to see the overall health and fitness benefit. You have to look at exercise as part of your life to maintain your life. As you age, without intervention on your part, your fitness level will decline, slowly at first, so slowly that you won't even notice it. Your rocking along and all of a sudden you realize that you can't do something that you were able to do without batting an eye.
I look forward to my, now daily, workout. I can breathe better, walk better, farther, longer. Working out saves me money on health insurance, lower weight=lower premiums. I can lift that 50 pound dumbbell multiple times, now. The road may look boring, but that mountain top view at the end of the road is worth the drive.