My first three legacies only have two or three generations, but I've switched focus over to the first heir to reach YA. It's hard though to give up writing about the other family members, probably because I'm used to switching around. With one family, if I try to focus only on the heir and his wife, I'm left with little to write about since they mostly eat, sleep and work, not interacting much with each other. So if the parents and younger siblings are doing something interesting or which I can piece together into a plot, I still write about them.
actually, with that couple, I didn't even switch over completely until they were married. Might do the same with the other two heirs, who are still single. I'd hoped to have both meet their spouses while teens, but that didn't quite work out.
