Spreadsheets are very useful when you are dealing with a many numbers with quantifiable amounts. They are especially useful when you want to track finances, where large numbers are involved. Similarly, the following instances may also be appropriate for spreadsheets:
1calculate the amount of mortgage payments or car payments
2create specific budgets for things like vacations or a wedding
4generate graphs
5compare prices
7calculate your net pay
8predict how much you will save in a certain amount of time