I'll be using an office in my home.
Is your home zoned for use like that? Doing white collar stuff from home is no biggie, but as soon as you have customers showing up all - for any reason - all that changes. For one, is you home ADA compliant? If not - and there are people who pretty much make a living at it - you could get sued for not being ADA compliant, even though you don't have a single customer who would require it. One club I work at was forced to buy a huge, complex, and needless to say very expensive, lift/platform to accommodate wheelchairs, in the four years it's been there, it hasn't been used once.
What's your liability exposure? You're making a video at there in your 'studio' and someone trips over a cable (and as a stagehand I can pretty much guarantee you that if there is a cable out - no matter how small - someone is going to trip over it), who pays for the damaged equipment/damaged human?
And the lawyer is not just in case you get sued, but more to make sure that all the i's are dotted, and the t's are crossed. You've looked into the registration of the business, and the DBA statements. How about the sales tax permits? Will you have to charge sales tax? What about health/environmental regulations? A good friend who moved from being an amateur photographer to a professional one got in trouble because his home darkroom (all perfectly legal so long as it wasn't commercial) didn't have proper warnings posted for the toxic chemicals that darkrooms use. He also had to install a rather pricey ventilation/filter system too as I recall.
The lawyer will also insure (if they are good) that your contracts are rock-solid and iron clad, and that you're web site/advertising ain't writing a check that your ass can't cash. If Mixie even as much as vaguely implies that with her help you will pass the test, she's got a huge exposure when someone doesn't. Or if you get hired for that particular slice of hell known as filming weddings, what kind of contract do you have in case (and it happens often) that the wedding is canceled?
If you are filming in public, on streets or parks or the like - will you need permits to do it? (Bet you do).
There is a bottom line point that money changes everything. As soon as any money - even a dollar - changes hands, you're in a whole new set of conditions and circumstances.
Red Adair was right. I work for one of my union brothers who also owns a C-10 contracting business. He often loses a job when he quotes them a price, only to wind up making more money as the cheerer labor screwed it up and now he/we have to go in and not only do the original job at full price, but undo what the the cheap people did (also at full price.)
Here is a great little bit. Written by Ira Glass it's talkign about art but you can think of all sorts of other things that it's also true about, like running a business.
"Nobody tells this to people who are beginners, I wish someone told me. All of us who do creative work, we get into it because we have good taste. But there is this gap. For the first couple years you make stuff, it's just not that good. It's trying to be good, it has potential, but it's not. But your taste, the thing that got you into the game, is still killer. And your taste is why your work disappoints you. A lot of people never get past this phase, they quit. Most people I know who do interesting, creative work went through years of this. We know our work doesn't have this special thing that we want it to have. We all go through this. And if you are just starting out or you are still in this phase, you gotta know its normal and the most important thing you can do is do a lot of work. Put yourself on a deadline so that every week you will finish one story. It is only by going through a volume of work that you will close that gap, and your work will be as good as your ambitions. And I took longer to figure out how to do this than anyone I've ever met. It's gonna take awhile. It's normal to take awhile. You've just gotta fight your way through."