To make sure you end up on the happiness side of the equation, you need to manage your annual budget properly. It's tough to get a handle on your annual finances--but this excellent, free Excel spreadsheet helps. lists every category of income and expense you can imagine. All you need to do is fill in your estimates for the coming year, and you'll see whether the likely result is happiness or misery. If the answer is misery, adjust your estimates until the numbers add up right--and then, of course, follow through on your budget.

There's one shortcoming in this spreadsheet that you need to keep in mind--it has no area for your taxes. So when you fill in your income, only input your net income (including interest income and dividends), not your gross.