How much income are we talking about?
At the moment, not a whole lot -- little enough that I expect to be able to put
all of it (net self-employment taxes) into a solo 401k (this year, at least). That might change in the future... or my wife might get a full-time permanent W-2 job and that would be the end of it.
I guess what I really want to know is, would being something other than a sole proprietorship be useful enough (now or in the future) to be worth the fees and/or paperwork?
Some background/details would probably be helpful:
My wife is a graphic designer. She's currently working as a 1099 for one company in a way that's probably worker misclassification... but such misclassification is so common in her industry that at this point we're just going to roll with it and hope the benefits of a solo 401k outweigh the costs of self-employment tax. Also, instead of pushing to be reclassified as W-2, she'll start pushing to be treated as a "real" contractor (in terms of autonomy and pay) and try to find multiple clients and whatnot. However, I don't anticipate it ever growing to the point that she has employees or anything like that.
(For the other company she works for, she gets paid as a W-2 employee of a contracting agency middleman, doing similar work under similar circumstances. I'd also love to have advice about how to negotiate with the company to cut out that middleman.)
The other thing is that we've got some aspirations -- that are mostly nothing but idle ideas right now -- for some other types of unrelated business ventures (e.g. landlording, creating indie computer games, etc.) and I have no idea whether it makes sense to have zero business entities (to it all directly in our names), one business entity to handle all of it, or a separate entity per venture.
Practically speaking, do I want to file the SS-4 as "[wife's name as individual]," "[wife's name as individual] d.b.a. [wife's name] Graphic Design", "[wife's name] Graphic Design, LLC", "[family name] Ventures, LLC d.b.a. [Wife's name] Graphic Design", etc.?