There is a formula for knowing when to retire, and here it is.

Let's say you've worked for X number of years at your current job, and you're looking forward to a time that you don't have to do it anymore. Not another day. How do you know when that time is? I think it comes down to a formula, to three things: (1) job satisfaction or lack of it, (2) assets, and (3) future plans. If you've thought about all these, and you still want out, then it well may be time to retire. But if you have hesitations, maybe you need to think about it a little more.

Take your current job: Are you happy? Do you like it? Would you miss it? Lots of people are so wed to their jobs that they can't imagine not doing them. This may be because they truly enjoy their jobs, or it may be that their jobs are the anchor in their lives: cut loose, they would drift, and with no money. Others can't wait to be done with their jobs. Categorize yourself: which are you? If you're the first, then hang on to your job as long as you can. (But do try to retire before you're run out by young management. Keep your dignity.) If you're in the latter category -- ready to quit, for whatever reason -- you need to pay heed to number two above: assets.

If you could give up your job tomorrow -- or next week -- with no qualms, then it's time to think about whether or not it's workable. Consider your assets, your financial situation. Can you afford to stop working? Paychecks are very addictive. Can you do without them? Forever? If so, if you have enough saved and maybe a pension or 401K money or investments, plus Social Security, etc., then you need to move to the big one, number three: future plans.

If you're just quitting your job because you're sick of it and you can afford to, consider this: What will you do when you're not doing this job? Are you ready to spend whole days doing something that won't drive your spouse -- or you -- crazy? Do you have a hobby? An intellectual pursuit you've put off till now, like reading history books or writing a novel? Are you really prepared to fill up the rest of your days on this earth with useful or at least entertaining activities?

Can you, for hours on end, not be supervised?

If you answered "yes" to all three -- you're ready to quit your job, you have enough money to get you through the last decades of your life, and you have something to occupy all those years that you really want to do -- then it's time to retire.

What are you waiting for?