I like to use some non-standard skins in my game. Some of these are extra-large, like the Rubenesques and RubenDudes from Mermaid Cove, some are just unusual, some are pregnant. If these Sims follow the standard "career" paths, every time they go to work they change into work clothes, which in Sims 1 use the standard body shapes.
Also if playing themed historical neighbourhoods, a modern carpool turning up is seriously anachronistic. Magical Sims also need to have some income while developing their skills.
There are different ways to solve this problem - one way is to edit the careers, or to make new careers, which don't call work outfits, or careers which call appropriate career outfits.
The game cannot have more careers; if you add new careers, you have to swap others out. So, the remaining options are non-employment or self-employment. Therefore, quite a few of my Sims are self-employed. Many of the possibilities here are not mutually exclusive - for example a Sim who is in the Education Profession may use the Work at Home computer for paperwork days, work on equations at times, and maybe use a professional telescope at night.
I've collected some possibilities, with links to the sites where the required items are still available. I know there are more out there and will continue to add links. (If you have or find any please contact me!)
One item that can be very useful for Sims who work from home is the Get paid Time Clock which comes in many forms: an Abacus, an Hourglass, a Ledger Book with feather quill and ink well, an In/Out Chalk Board, an Industrial Time Punch, and a modern Card Swipe Clock. Several of these work well with historical themes.