I do this all the time! Mostly because I hate seeing my sims just stand there and doing nothing waiting for me to tell them what to do! Even when I'm controlling them I still keep autonomy on. It does get really hectic when your controlling more than 3 sims though! What I usually do is I usually like to raise their skills and max out their jobs/careers before I just sit back and let them run automatically! Then when they have kids I focus more on them until I raise up their skills and then just let them run automatically as well! They almost do a good job taking care of toddlers! My only thing is I wish they would feed their pets and fix things!