Back in the Sims2 days I set up this system of sending teens off to Uni with expensive items. Once they moved would sell the stuff and expand their house, add nice furniture open and fund expensive vacations after exams. And because the way the game was set up, each new group who went to Uni would get to stay at the same house.
In Sims3 and Sims4 I've had to change my approach. Now I'll "adopt" worthy (or cute) sims into a household, let them stay long enough to build some skills, get a job, or until I get bored with them, then I put expensive violins in their inventory and move them out. After that, I can play the sims and help them spend their wealth, or let them visit once in a while.
And I have one family that just opened up their 4th restaurant.