So I don't actually intend to touch most of it (all I want to tune is the lifespan multipliers for supernaturals so that fairies aren't practically immortal) but I'm wondering about the entries regarding "aging years" and aging stage lengths in AgingManager.xml. Those just determine the defaults, right, there's no need to actually mess with that to make it match what's set in the game options?

I'm playing on a Long lifespan, but with a couple of the values adjusted a little bit from default. (i.e. I set babies back to 3 days because they're not fun to play with and added a couple days to the toddler/child stages to compensate)

I learned to just edit the options.ini file your Documents/Electronic Arts/The Sims 3 folder. It allows for greater flexibility than the sliders. I don't think I did anything else for aging length.

Right, I have my stuff set in the options.ini, I'm just curious about these entries in the XMLs.