I usually have three of four save games that I play in turn. One I play a single runaway teen, one has 8 sims and I'm on generation 8 as well, one save file has 2 YA and their first child and the last 'current' save file as a single YA but in this one I have aging off.
I was playing another save file where I was playing rotationally but it just became too messy with all the game assigned 'lovers' so I've got that file saved on my desktop at the moment but in the rotations I had households ranging from a single sim through to 7 sims.
I really enjoy playing with larger households and even the households I start with just one sim always end up full!