You consider buying better quality vegetables to resell for higher profit. Your grandmother advises you to pay an advance toward your school fees now, when you have a little money in your hand, so you can't spend it on other things.
What should you do?
You think grandmother's advise comes from long ago. You invest in growing the business, hoping to save faster to pay for school.
Why take a risk for more money tomorrow when you can take a step toward your goal today? You pay ahead for some school fees.