After this movie I was thinking, is it possible to see the future? As long as I know we still don't have the machines, that predict it, do we? And yet, I think, more or less you can predict your own future. One of the ways is to create it, yet another one is not to do anything and that means to let somebody else to create it for you. In one way or another you still are able to know it. Of course, you won't know the exact details, but the main stream is obvious. Probably you are not going to know what color house or car you are going to have exactly, but you can be sure what house or car you are going to have in general. Probably you are not going to know what exact holidays or relationships you are going to have, but you can be sure from which range you are going to choose that. All other aspects of life can be predicted the same way. And all these predictions are based just on your today actions. There are a lot of methods to know what actions or no actions lead to what. One of them is to look at other people who are doing similar actions longer than you do and to see what their reality is now. Their present is your future. So, the fact is that you still are able to know your own future. You might ignore this fact, but it's not going to change the way it works.
Going back to the Paycheck, what is Jennings doing when he already knows the future? He acts. And he acts fast to change it, because he knows that there is no delay. The clock is ticking and the time is lacking. If you knew that the nuclear war is coming would you still choose to stay with all your excuses why you can't do anything? So, if you already can predict future based on your today actions and you like it - perfect. That means your are going to create future of your desires. The other thing is when you don't like the future, your today actions lead you to. In this case you can change the actions, and I encourage you to do it fast, because everyday you are loosing time of your life, doing things that won't create your desire future. Don't wait for a nuclear war to happen to be sure you can't change anything.