How often to change the air filter?

I have a 2004 Nissan Maxima and commute about 70 miles every day. How often should I change the air filter?How often to change the air filter?Every 12,000 miles.How often to change the air filter?the easiest way to find out if the filter needs to be changed is hold the filter up to a light and if you can see light through it then it is good. if you cannot replace the filter.How often to change the air filter?u should change it like every 3 or 4 month it depends to if u live in the city or country area.How often to change the air filter?change it whenever it gets dirty.How often to change the air filter?I'd read the owners manual and get the proper answer - but thats me!!!!How often to change the air filter?it's usually about every 30,000 miles