I own three International 4300's. 2004, 2005, 2008

I try to do some of the mechanical work on them, but my knowledge is limited. I have learned that if I take the time to look at something before I call my mechanic, I save a couple hundred bucks here and there... and have a better understanding of my equipment.

Is a code scanner worth the money for me, and which one(s) should I consider? Is "code scanner" the right terminology?

Thanks!!