I used to play with full households even above the 8 sims limit, but don't find that as much fun anymore nowadays. Managing three to five is my sweet spot now between it being boring and too much work.
My playstyle is autonomy off, since free willed sims act and rout too unpredictably, not to mention inefficiently. If I have to keep autonomy on for specific challenges, I feel I'm more often canceling unwanted actions than actually giving instructions. It's an uphill battle that I don't want to fight. Same for the nanny, my poor toddler had to constantly keep nanny occupied so that they didn't break stuff or fill the house with half-finished dishes.
The pause-key was already mentioned a lot, another thing working in my favour is to keep aging off. With no more time limit it doesn't matter when the sims reach their goals. (Going by that logic, I perhaps should allow free will, but I just can't. It drives me crazy.)
And finally I cheat. If I see a sim approaching mine for some unwanted chit-chat or if a conversation goes downhill and I cannot cancel quickly enough, then I sometimes use shift-click "reset object" to regain control. Resetting townies this way can be a sanity saver.
