My kids both worked in the summer and used the money for their discretionary spending at school. As it turned out, one summer my oldest kid got a job at her university that she loved (she did calling for the alumni fund–a job I’d hate) and she decided to keep the job when she when back to school in the fall. She also worked as a gymnastics coach at a local gym (mostly working with young kids) two days a week–a job that she kept after she graduated because it paid more than the alumni fund. She kept coaching until she found a job in her field.
Younger kid worked in the summer, but didn’t plan on working during the college year. After freshman year, D’s advisor offered her a baby sitting job. Two days a week, D picked up the advisor’s kids from school, drove them home, and made dinner for them. The advisor was extremely generous and gave D $250 per week–she worked about 8 hours a week.
We didn’t tell our kids that they had to work, it just turned out that they had the opportunity to do so and decided to take it.