Need more information about the vehicle and what type of oil you're using. Traditionally, it's 3000 miles, but modern oil filters don't normally have to be changed as frequently.
Change your oil filter at each oil change. That can vary from 3000-10,000 miles.
Consult the owners manual for the manufacturers recommendations.
Change the oil filter every time you change the oil.
Change the oil filter every time you change the oil.
I change it every other oil change.
If you drive normally change the oil/filter every 8,000 miles.
Often times coupons for an oil change will include air filter as this is often done routinely with an oil change. A person should read the coupon to make sure though.
Every other oil change.
My recommendation is every 5,000 miles change the oil & filter.
Usually the oil filter of the car is changed when the oil is changed. The oil change should be done on regular bases after like 3000-5000 miles or when the car is brought to the garage for a service.
Follow the manufactures recommendation or change the oil/filter every 5,000 miles.
Saturn recommends changing oil filter every 6000 to 12000 miles. Most mechanics recommend changing the oil filter with every oil change.
Depending on how much you drive your car should be how often you change your air filter. Sources say you should change it when you go to get your oil changed cause they both last about the same time.
If you use conventional oil then I recommend you change the oil/filter every 5,000 miles. If you use synthetic then change it every 8,000 miles.