Question

Why should you track and record your spending and income?

Answer 1

You could manage your spending more efficiently in the future, therefor you learn to save money and or build credit history. In-order for an individual to get an accurate estimate of their income, they'll need to keep track of their spending.

Answer 2

You want to make sure you're never spending more than you have, to keep yourself out of debt. Unless you're trying to build credit, you don't want to go into debt.

Keeping track is very smart, it helps you budget, and in cases where you use a debit card that takes several days to actually take the funds out of your account, it helps you make sure you're always able to pay for what you buy.