I haven't seen this posted here so I thought I'd share what I found.
We've all been there when our sims gets a promotion and ... GAH! What the heck are they wearing! Case in point, my politician sim changed into a suit (great) with flip-flop sandals (facepalm). The painter career is famous for some truly hideous outfits. And you think to yourself, well I'm stuck with this until their next promotion.
Not anymore! I have to give credit to the original poster over at Mod The Sims, Lynire. Here's the link to the original post:
http://modthesims.info/t/568751This involves no mods and doesn't require
testingcheats on to use it. To make this easy, simply have the offending sim selected, open the cheat console (Ctrl+Shift+c) and type
sims.modify_career_outfit_in_cas. This will immediately take your sim into the CAS and they will be in the career outfit.
Things to be aware. If the outfit they are in isn't available in CAS (for instance, my politician's suit couldn't be found) then know that if you change out of it, you won't be able to change back except with maybe the Undo arrow. Someone also posted they couldn't do earrings.
There's also a further cheat listed in the post but is a bit more complicated and I would imagine would only be useful if you wanted to change a non-household sim's career outfit. I won't list it here but you can find it at the link listed above.
Happy simming!