Both of my current save are Simlit stories so I don't use story mode for creating sims. My stories are a mix of gameplay influencing what I write and using my game to stage screenshots for storylines I've written in advance.
A lot of what I do in CAS depends on whether they're going to be an important character or just an extra. If they're a main character I already have a good idea what traits, jobs, etc I want them to have. If they're going to be an extra I won't be playing that household so I just give them generic traits and just pick a random aspiration. I have a mod that gives each new household 100K, plus 15K, for each additional sim. I like it since I can put new characters into whatever lot I want, within reason. It saves time and extra steps.
For main characters I usually furnish their homes with decent appliances and furniture. Stuff that's good enough that they're not constantly having negative moodlets because of bad food or a poorly decorated home. If their backstory makes sense for them to have the best of the best I give them those items. I'm a benevolent watcher, what can I say 😁
