In most cases, no one has money at university. I rarely make money at parties. There is nothing wrong with this, but few people feel guilty about spending too much money.
Implement a sensible economic habit. It contains all the common things. Keep costs low, set budget, repay debts as soon as possible, Maintain emergency funds. Your income may fluctuate in your 20s. This is normal, and in most cases it is comparatively less than your control. But you can control your economic choice. I will continue to live like a student until your situation is more stable
Time also changes. When you spend someone else's money you are really just spending your time. For example, most college students in the U.S. do not pay for all universities themselves. Their parents will help them to a certain extent, such as rent, tuition, food, clothes. As a college student, I often see people waste these "money" on what they really do not need. The most interesting thing is that if you take everything and move to a forest somewhere and do yourself, you can get it anytime. Time is valuable only when we need property. If you work 40 hours a week and you dislike the time you spend on weekends, should it always be 'free'?
First of all, I would like to say that your problem is based on the erroneous premise that "most college students spend too much time and money for pending major students". It is clearly wrong. Some students waste money by changing professional / failed courses. Finally, I think I will add this ... changing your profession is not a crime. To grow between the ages of 18 and 22 means learning yourself in such a way that you can not understand the real world without knowing it. A part of this growth may mean that your interest has changed legally and your future is different when you are 22 years old, when you are 17 or 18 years old I will.
Most college students spend too much time and money for undecided majors. What can you do to prevent high school students from entering university?