I realize it's a rhetorical question, but pretty much everybody in the arts? I'd be very surprised to find a professional musician that doesn't play as a hobby.
Artists and musicians surely have portfolios to show, but I don't think those are usually composed of things they're doing in their free time. Maybe? I'm not an artist so maybe I'm wrong. I guess then we're back to "you should have a portfolio" rather than specifically "you should do your job in your free time." I can agree with that!
The equipment is irrelevant. What other career out there expects that practitioners also perform the work at home during their free time as a hobby?
I realize it's a rhetorical question, but pretty much everybody in the arts? I'd be very surprised to find a professional musician that doesn't play as a hobby.
Artists and musicians surely have portfolios to show, but I don't think those are usually composed of things they're doing in their free time. Maybe? I'm not an artist so maybe I'm wrong. I guess then we're back to "you should have a portfolio" rather than specifically "you should do your job in your free time." I can agree with that!
I have written software for laboratory devices on similar price levels, that will never run on home computer.