Rent or buy?

QIs it reasonable to buy a house if I plan to move within a few years? — E.W., Flagstaff, Arizona

AIt’s a risky move for several reasons. For starters, home values don’t always go up over short periods. Your house might fall in value, and when you want to sell, you could end up owing more on your mortgage than the home is worth. Then there are the closing costs when you buy, and the agent commissions you’ll likely pay when you sell. Those can total many thousands of dollars.

Meanwhile, mortgages typically require you to pay mostly interest in your first years of repayments, so you won’t have built up a lot of equity. You’ll also be paying for insurance, property taxes, maintenance and repairs while you own the home.

Renting is often the smart thing to do. Sure, you don’t get a mortgage interest tax deduction and you don’t build equity. But if your rent is much less than your mortgage payment would be, you can invest the difference and build a little nest egg.

Do your own math via a rent-or-buy calculator at Fool.com/calculators.

QHow can a company’s earnings grow more rapidly than its revenue? Shouldn’t they grow at a similar rate? — K.H., online

ARevenue (also known as “sales”) is at the top of a company’s income statement, while earnings (or “net income”) is at the bottom; a lot happens in between.

If a company’s revenue holds steady but its costs (such as raw materials, salaries, advertising or research) rise, its earnings will shrink. In contrast, if a company’s earnings are growing faster than its revenue, that suggests it’s becoming more efficient and its profit margin is increasing.