The best advice about writing for a living I ever got was in a book I read as a young aspiring writer. It was to the effect of "Most people who say they want to write actually want to 'be a writer'. If you can be happy doing anything else for a living, do that instead. Only write if you feel like you'll go crazy if you don't."
I'm not a writer, but I do write, and I also read this advice when younger then promptly ignored it. I think it was from Bukowski.
It sounded, and still sounds, like "Only run if running bursts from the soles of your feet and you feel like you'll go crazy if you don't." Well, no. It might be good advice for a professional athlete -- I wouldn't know -- but you can run whenever you damn well feel like it as an amateur. So too for writing.
I got that advice too, but now I feel like they say that about every profession