I've always enjoyed the idea of turbo timers. Had a friend building tuned DSM Mitsubishi Eclipses that put turbo timers in lots of stuff, and they varied the run time if it had been driven hard.
On our PM diesel we make it a point to just let it sit and idle for a bit, especially at something like coming into a rest area directly from the highway.
Recently I added an Ultragauge to pick up extra information. One of the numbers that I have up all the time is the 'cat' temperature. Not exactly sure, but I think its the temp at the DPF. I can watch it climb up to mid 700s during highway cruising, but it quickly drops down to low 300s or even 200s at idle. So now I watch the DPF temp drop to that idle temp for awhile before shutting it down.