By this stage of the game, every person who is old enough to read knows that if you want to live a long and healthy life, you have got to work out on a regular basis. Granted, you could always just try and starve yourself to stay thin. But in time, your metabolism will fade, you will get lumpy, and you will also notice that you are growing weaker. Muscles need to be worked, if they are going to work properly. And while some people think that working out on a regular basis is nothing more than a matter of being motivated, this is a total delusion.
If you want to actually work out, you have got to overcome the little passive barriers that are standing between you and working out. For instance, if your gym clothes are not easily available to you, you are going to have to look around for them. This is going to be one more thing to do (and a hassle, at that), so you will just end up not doing it after awhile. This is how the human mind operates, whether it sounds good or not. You only have so much will power, so you might as well devote it to doing the most important things, while you do the easy stuff (like working out) automatically.
How do you do this? This is the simple part. All you have got to do is list out every step that takes place between, say, getting up and doing your workouts. Think through every step that you have got to take, and eliminate the steps that are not necessary. Then make the necessary steps as easy as humanly possible. Once that goes on, you are going to find that making it to your workouts becomes less a matter of getting yourself motivated, and more a matter of just going through the motions.