Something you may want to consider is filling your tires with nitrogen. Check out this 3 minute video done by fellow auto enthusiast Jay Leno in his famous garage.

He also mentions a common problem we all have when we fill our tires with regular air... water inside your tire!

LINK--->

 

Nitrogen isn't worth the price unless its a track car.

 

Also air is 78% nitrogen to begin with. Nitrogen's only benefit is that once a month you don't have to check your PSI because it shouldn't change much... but it's still good form to check.