This article on the link of your child having a job and being successful in high school and college was covered in a recent Professional Development. Ostensibly an AVID assignment, it appears to have been chosen to provide a discussion point for a class.
Young people who have held jobs are better students because they know they can’t do everything at the last minute, all at once or erratically. They whine less, they make fewer excuses and they don’t expect something for nothing — like, for example, an acceptable grade for unacceptable work. They wouldn’t expect to get paid for showing up every day if they didn’t do anything and yet some of their more spoiled counterparts, shockingly enough, actually believe the should get a “pass” in a course simply because they showed up for every class.
I tried it in a number of my classes and the consensus from students that had jobs matched this one, that they could easily spot those who had a job by their work ethic and attitude in school.