Good article! I've heard more about underinflated tires lately, yet I've not checked mine. Shame on me.
Yes, you should check and adjust your tire pressure often. Check tire pressure first thing in the morning when the tires are cold; preferably before driven more than three miles. Adjust the pressure to the car manufacturers recommendations. However, it is more important that the both front tires are the same pressure and that both rear tires are the same pressure than they be the correct pressures.
Some tire sellers are using nitrogen instead of air to inflate tires, which decreases the rate of loss in air pressure. You can later mix air to the nitrogen.
We are all lazy, roatate them, then check the pressure, do it when you have the oil change done. Save fuel, save tire wear, save yourself! Do I do it all the time, of course not, but we all should. :)