Not good advice. First the airlock is not a gauge for fermentation, it just lets extra pressure out. There is a video floating around with an empty carboy that has an airlock bubbling away. It can be a temp increase or a pressure increase. The only way to tell if you are ready to bottle is to take a hydrometer reading and then another one a few days apart. If the gravity is stable, then it is safe to bottle.
Every fermentation is different. The yeast operates on its own time schedule not yours. That being said, you are usually safe to bottle after about 2-3 weeks once the gravity stabilizes. Extra time will not hurt the brew, but actually will improve it.