My father told me once that our family's position on enlistment is "If they call your name you serve and you serve honorably and you serve the minimum, but you don't volunteer."
Funny enough, after doing some genealogy on my father's line, this appears to be the wisdom going back to the American Revolution. My 6th-great grandfather was ordered to serve in the revolutionary war, he served 3 months, saw one battle, and went home -which was apparently enough at the time to get him a full pension (he had to sue for his pension which is how we know the story).
None of my other g-grandfather's in that line served in the military until my grandfather was drafted in WWII. He got put on radio duty in Oklahoma.