I worked as a student secretary at my school. Hours were flexible, but only between 8a-5p M-F. My second job was to transport and supervise DCF (some places I hear call it DCFS I believe) visitations between children removed from care and their parents. That job has more flexible case times since it could be evening or weekend if need be, but once a case had a time slot it typically shouldn't change (which was hard when clinicals kept changing every month or so).
I think it made me use the time I had more effectively as a student. Knowing I had to work at least somewhat to keep my head above water financially, I knew it wasn't an option to slack off or not work. What was really difficult, though, was when there were group projects or group quizzes and said group doesn't care that your hours aren't so flexible or that you need to work. A lot of my classmates were still living off mommy/daddy or their spouse was paying the living expenses (they didn't work at all or worked very little during the program) so they didn't quite get it and were not the nicest about having to work around my work schedule. In that aspect, working absolutely made it harder to succeed as a nursing student. But at the end of the day, you've got to do what you've got to do! I had one classmate work full time night shift the whole ABSN program! I doubt she'd recommend that to anybody, but she had to work and somehow she managed to survive the whole year.