[TransAm]

Important question, though very often overlooked. When your car's engine air filter clogs with dust and dirt, it makes the engine less fuel-efficient (could be up to 10% fuel efficiency that you lose). Not only that, but the air filter cleans the air that circulates inside the vehicle while you drive. So, if you can, have it checked at each oil change, and change it regularly according to the manufacturer's recommendations.

[MomVan]

I will admit it's been awhile since I've had it changed. I believe I'm about 6 months past my oil change date too. I guess I'll break down and get that done within the next couple weeks.

[Byker]

I used to neglect to check my air filter, but when gas prices started going up a few years ago, I wanted to get every mile I could out of the gas I buy. Now, I check it at least every time I change the oil.