For Those Playing Legacies: When Do You Switch Over Focus From Previous Generation to the New?

I would start focusing the story telling on new children as they started growing and were starting to do more things in life though I'm playing my entire town in legacies.

I tend to shift the focus when the heir becomes a teen, just cause that’s when they can start to fall in love with potential love interests and I just really like the teen life state .

I like to play with everyone in my sim's family. I even enjoy checking up on their pets throughout the day. Right now I'm keeping everyone in the same family on the same lot. Any spares will move out on their own after university. I like for everyone to have some sort of goal they're working toward or a hobby they enjoy so I suppose all the sims in my household get a focus. So I guess this is a nonissue for me.

Letting go of spares though.... That's going to be a challenge for me.

I usually start to focus on the heir once the parent has completed their LTW or the traditional way when the heir has finished Uni and is now a YA.

Currently, I'm playing a game with rules I've made up (not ready to share the rules yet, just testing things out) for a legacy. In it, the heir doesn't begin control until the parent hits their LTW AND reaches level 10 in their chosen career. Kinda tough, but makes for interesting gameplay.

I never drop the parents really, but as for all of the other non-heir siblings they get the boot after completing their LTW. Makes for very full households depending how many kiddies each gen has but I like to give them all the best lives I can. And then when they're about a week from death I move them back in (only so I can take pictures for the folder of 1000+ pictures on mg desktop).
For example current household is Alex, his twin Ailieah, his wife Becky, their 5 kids Matthew, Marissa, Margaret, Lola, and Logan, Logan's girlfriend Abrianna, and their daughter Summer, plus cat Puddy and dog Maya.
Marissa and Margaret are both at level 8 of their careers, so once they become level 10 they'll both go to some random house in Lucky Palms. Matthew is a little bit further from his still. And Lola and Logan have only been YA's for 4 days, so Lola won't move out for a while.