A former professor of mine wanted to be a fine art painter, so he opted to work as a professional portrait painter. You would think that this job would be great, since you essentially get paid to be making oil paintings all day. However, the reality is that being a portrait painter can be nightmarish. His clients always seemed to have a vision of themselves that had nothing to do with what they actually physically looked like, and they complained left and right about every single petty detail. He found himself creatively bound by unreasonable demands made by clients, and having to pander to their desires. This basically dispelled any shred of creativity from the portrait paintings, making the process very mechanical and constrained.
One of my peers went to art school for animation and upon graduation landed a full-time job at a small, independent animation studio. Sounds perfect, right? Well, it turned out that his job animating all day long (and many times all night long) was so demanding and exhausting that by the time he got home at the end of the work day, the last thing he wanted to do was animate more. The job was consuming to the point that he couldn’t muster up the mental space or the time he needed to work on his own animation projects outside of his day job. Within a year, he had left the studio. On the flip side, I know plenty of people who work at animation or production studios who are plenty satisfied with their work there.
There can be advantages to separating your art from your paying job. If your paying job is completely unrelated to art, you’ll have more mental space and energy for your own studio practice. One of my former professors told me that he was a movie theater manager when he first got out of school. He said it was a great schedule because he could focus all of his energy on painting all day, and then go to work at night. A department head at an art school told me that he was a waiter for 15 years, and during that time, produced tons of paintings. By contrast, he now paints very little due to the administrative demands in his position as a department head and professor of fine arts. While having a job that is completed unrelated to art works for some people, there are many of us who would not be willing to be a waiter for 15 years.