Sometimes it's hard to choose a kerbal for a mission because they are all the same... well, they differ in courage and stupidity but they have no history, no personal merits they have achieved. Do you remember who was the first kerbal in space? No? Ok, who was the first kerbal on Mun? Still no idea?
The Final Frontier plugin will handle this for you. Each kerbal will get ribbons for extraordinary merits. And the number of missions flown (i.e. vessel recovered) is recorded, too.