When are trucks retired?

I'm in an 07, apu, no def. 300k miles. They're threatening me with a new truck. Dang it, I like Jolene... (wifey named it).

 

My 1st truck here at Gordon was an 02 and had 1.2 million on it when I got out of it. I was in it for a few months, my last 2 trucks have been 2011's....1 with and 1 without DEF. My current truck was just in the shop last week and I was in an 02 with 1.1 million as a loaner for a few days, it sure ran good. I know my first truck was rebuilt at 650k (in frame) but I had a lot of stupid little type problems with it, mostly air system stuff (rotting bags, bad lines, etc.). You won't be in that old one long before they put you in a Cascadia.