Sorry i missed your second question. Plenty of characters are still alive. Characters retire into NPC formats, generally once they are lords and such. There is only so many apocalypses you can have to challenge high level characters. They can come on "screen" in other campaigns. They generally have their own faction that they operate off camera. New characters sometimes opt to be sons of earlier characters of their own, or of other players characters. It works quite well.

I have had to add a magical plant, which when processed, slows the aging process. I felt a bit harsh killing retired characters, so the rich and powerful tend to not age too much. Some players are fine with their characters to die off, but thats there choice.

Lastly we sometimes dust off old characters to deal with major problems or just for mainly RP type sessions.