How Do You Manage Your Population?

Do you use mods? I use MCCC for story progression, and every now and then I will go through all my neighbourhoods and move in random sims/families from the gallery to fill my population. I move them all to unplayed households, and MCCC lets them age, pair up and get married automatically, have children etc. And then when it feels like I need more children because my legacy family is about to start a family, I'll move in a bunch of families with young children. And when my legacy sims are YA then I'll move in a few single YA's to socialise with/meet and start relationships. I really like how it works. The sims I've chosen get married and develop these lives without me having to do anything much :)

If I didn't have MCCC I'd probably do the same with downloading sims from the gallery - it's a really quick and easy way to keep things fresh, and change populations, without having to do a huge amount.