Whether you are just starting out or if you are an experienced exerciser, having a training program in place to guide your workouts is the secret to any successful routine.  A proper training program will instruct you exactly when to increase the intensity and how.  It will make your workouts more efficient and ensure faster results are met.  Basically all of the thinking is done for you and all you have to do is complete the series of tasks outlined for you in each workout.

The methodology of putting a program together is dictated by the ultimate goals.  Then, over the course of a year, it will be updated regularly so as to give the body a constant reason to change and improve.  The number of sets should vary regularly along with the repetition ranges.  More importantly, the type of exercises should be altered frequently as well.  If you are always doing flat bench presses for example, you should substitute that for a hammer bench press or dumbbells just to give the muscle a different feel and a different angle of attack.  And then when you do go back to the bench press a few weeks later you will be much stronger.