I play rotational with aging off. I build my sims world as I go with sims that are needed for other sim stories or story lines. I age them up as I wish and that depends on their story. Some never age.
I don't worry about a dead world. Everything is alive and well in mine and always evolving with characters I create to make it so. Every time new content comes out it is a guarantee that I add a couple of households to my save. Sometimes more. Or I re-purpose sims who have been waiting for new content and develop them with it.