Does your air filter housing have indicator on it? If it does do not change it until the indicator says too. Studies have shown that most dirt inters the system during filter removal. Instruct whoever changes your oil to do not remove the air filter.
You will not believe how dirty a filter has to get before it is even close to plugging or effecting your fuel economy.
I have been designing air filtration systems for military vehicles for over 30 years. I know what I am talking about.
I have 1 2004 Chevy Avalanche with 165,000 miles, uses less than a quart of oil in 8,000 mils and is only on its second air filter.
Why, they just don't require that many changes. Selling you a new filter is a money maker for them and a unneeded expense for you.
Believe the restriction indicator and stop removing your filter unless you plan on changing it.
AS for K & N filters - don't. The only way to get better airflow thru a filter is to add more media or make the media more open to allow air to flow easier. The reason they use oil is to help catch the dust because the paper can't.