Also, jesus, new character XP penalties are so so so sucky.
My PCs get to keep 75% of the XP of their previous character if they make a new one without their former character dying. I introduced the measure to discourage constantly switching characters, since some players literally had a list of future "Alts" to try (I have the full list in my face all the time when I open OggDude's excellent editor). Also, when you get into reallllly high XP territory, it's very tempting to get all creative and go crazy in the editor since you have so much room for variation. The downside is how it derails the narrative (constantly having to introduce new characters because the players want to "try" a new one) and oozes of a weird opportunistic metagame/minmax feel. If a player switches for the right reasons, I will adjust his XP level in time very subtly and it evens out. If a character dies (which has not happened yet) they will get to keep almost all XP since it's not a voluntary choice.