The time between air filter changes varies depending on what type of roads go into and are in campgrounds. If you travel on paved roads all the time, filter could last for years, on the other hand if the roads leading to and in the CG are dirt you have to change sooner.
Last year I changed mine with 4 years on it and was asked by my friend who did it "What did you do, shovel dirt into it?" That's how dirty it was. The gauge was still in the yellow.
Now will change every 3 years. Prevention is #1.
2005 KSDP 3910-----2007 Jeep Liberty
THE MIND IS LIKE A PARACHUTE, IT MUST BE OPEN TO WORK