The primary issue with the head gasket problem has more to do with the different alloys between the head and block, coupled with the large surface areas and expansion rates...a tall order for the head gasket anyway, which is really why failure would eventually occur. This is a known problem with the M103 and M104 engine series
One probable way to increase the life of your head gasket is to let your car warm up for a few minutes before heading off. This would allow the head and block to warm up and expand gradually, putting less stress on the head gasket.
I anticipate having to replace mine soon given the history of what other W124 owners have experienced, but at 113K, I have yet to pull the cylinder head off.
It's not really a bad thing, since valve stem seals will probably need attention anyway, and it will be time to inspect the timing chain as well...
2009 ML350 (84K) - Family vehicle
2001 CLK430 Cabriolet (71K) - Wife's car
2005 BMW 645CI (124K) - My daily driver
2012 Mustang V6 (60K) - Daughter's car