If the head and block surfaces are still flat and have a decent finish remaining. There is no reason a gasket of similar quality or better should not go a similar amount of time and distance.

I still feel it advisable to let the engine cool down and equilise hot spots when coming right off the highway before shutting the engine off. It will do no harm even if not particularily beneficial. Also keeps the lube going to the turbo bearings until the turbo revs drop down.