An engine for a military application has very different characteristics from that of a commercial passenger plane. The MTBF for the latter is in the 100k+ hours, with servicing usually performed around 10k.
There are several different tiers of checks, ranging from short frequent ones, to expensive, time consuming, infrequent ones: http://en.wikipedia.org/wiki/Aircraft_maintenance_checks
Usually, older aircraft that are being phased out are mothballed shortly before their next heavy maintenance check. And the resale value of used aircraft, especially older ones, is heavily influenced by how soon the next D check is.