If you aren't using resistance bands in your workouts, you're really missing out on a cheap and portable way to achieve a lot of your goals—on and off the course. One way they can really help is to train your body to swing faster in a safe and controlled manner. Not only are they great for getting your muscles primed for a round (you can park them in your golf bag), but they can help increase your swing speed. If you can safely swing five to eight miles per hour faster than you do now (an obtainable goal), you'll definitely hit it noticeably farther on tee shots struck around the center of the driver's face. The claim of 20 yards is supposed to entice you. Hopefully it did, but there is no hard-and-fast formula since too much depends on ball spin and launch angle. If you want a guesstimate, 2 to 2.5 yards for each mile per hour is likely.
So if you're ready to start pounding it off the tee, click on the video to watch me demonstrate a two-pronged attack to increasing clubhead speed with some stretch bands. The bands in the video are from SuperFlex Fitness and range in price from $21 to $80. You can get the handles for $20 more, but you don't need them. All in all, pretty affordable considering a new driver could cost you $500.