As a professional cleaning service located in the Greater Rockford area, I come across a lot of homes that neglect the high or low dusting of air vents. The job isn't very difficult, but can seem if you don't have the correct tools. Below I will provide links of some tools that will help with eliminating dust from ceiling fans, air vents, and cob webs in high corners of your home.
Cob Web Brush
Telescopic Pole for High Cathedral Ceilings
Swiffer Dusting Kit for Standard Ceilings
Also, check out this awesome video with tips to keep your home dust-free as possible.