Aging Characters

Every approach has been tried, it seems.  Some series have their characters age one year a book as in the Harry Potter series.  Other series hardly (if ever) have them age a la The Simpsons.  Then there are creative works where a character cannot age unless it is needed as a plot-point. 

I can’t really say which way is best but I do tend to like characters that mature more on-par with the rest of us when I am reading a series.  It doesn’t have to be a year per book but it helps to know time goes on for the characters I love, too.

There are a few exceptions to my feelings, though.  First, would have to be a series aimed at younger children.  If you made the characters all grow up, it would have to become a very different type of book if it was a long-running series.  A series with a formula that relies on things staying still is almost promised not to bend to the wishes of Father Time. 

Do you guys want your favorite characters to stay forever young?