I usually let the elders retire, once they hit the elder stage in order for them to take care of their grandchildren. If they do not have grandchildren, I move them out of the house after retirement and make them take care of other people's children so they can have a nanny 24/7 who gets no payment and contributes pension money for the house.
There's one peculiar retirement case I had, a rich Sim daughter of the Leader of the Free World. She chose the science career track and reached her LTW and Level 10 of her career. They were so wealthy, that I chose to have her retire even before she became an elder coz I hate her "mad scientist" uniform, she's so beautiful and she looked so silly walking around as a mad scientist! She's now at home speculating what career she'd like to go in next.