I only can think of one diesel car that the turbo doesn't last. In the newer VW Jettas if you don't excercise the turbo enough the variable vanes get stuck, also seems like they have a bad habit of injecting catastrophic amounts of oil into the motor when the center bearing fails. This oil in the zero clearance motor causes the connecting rods to bend.
Most gasser turbos do fail from coking which is caused by not letting it cool down. Up until last year my turbo with 100k miles (first 3k on dino oil) on it was as tight as the day it came off the line but some how the center bearing stopped accepting oil.
(there is NO coking in my turbo either, all I can figure was the opening rusted close in the time it set?!?) I got it back home before it failed but now it feels loose like any other gas turbo with that mileage. My rule of thumb for shutting the car down is to wait for my EGTs to go below 1000*F which may be almost instant if I coasted (cuts all fuel during coasting) a while or it may take a couple minutes if I just stopped boosting.