A note on retiring characters...
A retired character doesn't have to mean a dead character. Let's be honest here... what does an adventurer do? He fights a lot, he makes lots of people mad, he dies more than just about anyone else in the campaign world, and eventually he'll get himself some kind of killed he cannot come back from. Plus he gets a lot of treasure.
"Okay, guys. This was fun, but I'm done with the hassle. I'm taking my sack of treasure and I'm going home."
Who can blame him for that exit? This kind of exit is good for two reasons... 1.) It could certainly be motivational for his replacements. 2.) The character can be brought back into action at a later date.
Just my 2 cp.