I never understood the "trade him while he has value" argument. It's like trading in a car that still runs well "because it has value." If it has value, then keep it!
And in this case, we'd be trading in a car that runs well for an older model that's been in the shop a lot lately and doesn't run as well. Sure, the older one was a better model at one time, but I'll take a reliable Chevy over a sputtering Cadillac any day.