We don't usually trade ours in. We run them to the ground, and then get new ones.
My 99 Grand Caravan has 158K miles on it. I am hoping to get another year or so out of it.
We just passed on our 93 Grand Caravan with over 160K on it to DH's brother who is hoping to get a few more miles out of it...

Well, DH has a 97 Saturn SL2 with 220,000 miles on it and he is still driving it every day to work. He only uses it as his back and forth to work car.
It is falling apart, the bumper is held in place with duct tape and he 'patched' a small hole in the car with duct tape (both things happened when he hit a raccoon) but it runs still.
The a/c doesn't work so we are thinking about getting a replacement come summer but we will see.
We won't trade it in though. We actually know someone who works on cars that is willing to give us about $500 for it for parts.
He has good taste.DH drives a 92 Honda Civic. He doesn't communte far so he only has about 175,000 miles. The trade in value on the van is about $3,000 - if everything is perfect on it. We decided we will just keep it as our 3rd vehicle. DS who won't be 16 for 3 more years, has his heart set on his father's Civic.
DBF's parents gave him their early 90's Civic when he first got his license. It then was passed onto each of his siters when they started driving. It had a lot of miles on it and had been abused by each of them. (The youngest sister was backed into by a Mack truck in it. She was hit hard but it (and her) sustained little damage and it never skipped a beat.) The car ran perfectly fine and was reliable. Then they passed it onto their cousin when he started to drive. The car would have been passed onto his sister but he killed it. He decided that going from reverse to drive without stopping would be a great idea.
Kinda sad, it would have been nice to see how many new drivers that car could have handled.I have a 1987, 20 year old Volvo with 190,000 miles on it and have no plans to replace it.