Not really a right or wrong way to play the sims game. Bout as easy or as hard as you want it to be.
I have a few sims where I don't even look to get them a promotion and tend to keep them in the same position because I really don't want them to be successful or stupid rich. I do have a rich sim but there's still a bit of a struggle to keep paying bills with abig mansion wiht overly expensive things in it as bills are like 30K and it's only just them.
Sims don't even need any set of skills to get any sort of job across all four of them.
It's not like you go into options to change the difficulty of the sims. An casual, open sandbox experience.