Why You Need Backup EmployeesYou should have a replacement waiting in the wings, even for the star employee you love.

In his bookNo B.S. Ruthless Management of People & Profits, business coach and consultant Dan S. Kennedypresents a straightforward assessment of the real relationship between employers and their employees, and dares you to take action.In this edited excerpt, the author discusses why depending on just one employee for certain tasks can put your business in danger.

The worst number in business is one. One of just about anything is a bad thing.

In my home office, where I work under deadline pressure as an advertising copywriter, I do not have one Mac. I have three. Why? So when Mac No. 1 freezes up, crashes or requires an exorcism, I can move what I'm working on and urgently need to print out before the day's FedEx deadline to Mac No. 2. And in case Mac No. 2 has indigestion or leprosy that day, I have Mac No. 3. I keep them in different rooms to prevent contagion. My Mac is my employee. If Mac were a living, breathing human employee who, say, printed what I wrote in booklets on a printing press, I'd want at least two of those Macs and two printing presses. Never one.

Yes, this doubles your personnel cost. But that's an easier economic puzzle to solve than suddenly, abruptly being without the one person absolutely required to deliver a job on time to your most important client or to get tax reports filed before you're fined up the wazoo or to staff your trade show booth this weekend, where you intend writing 30 percent of your business for the year. I've had clients report their number-one and only salesman calling in to quit the day he was supposed to be jetting off to McCormack Place in Chicago for just such a trade show.

And, defying my own rule, by having my wife of some 20 years running my entire office, I was suddenly (and because of my own incredible myopia) served with divorce papers, a restraining order barring me from entering my own home and a resignation notice. Fortunately, I had a capable replacement readily available, and my wife was cooperative about the transition. But even so, it wasn't pretty, and it could have been a disaster. (For soap opera fans, we were divorced. We've remarried. All is well.) These are not freakish incidents. You could be affected by a similar situation if you insist on leaving yourself vulnerable to it.

Still refuse to double up? The next best things, poor substitutes but better than no preventive medicine at all, are cross training and, when possible, job sharing or job rotation. Cross training means everybody is trained in everybody else's job. Job sharing means two part-time people doing one full-time job. This is a quietly growing, trendy practice in corporate America that actually seems to work. Job rotation means two employees swap jobs during each month, Bill gets Job A the first two weeks and Job B the last two weeks, and Betty gets A and B vice versa. If all that seems awkward to you, wait until you see just how awkward the "I had just one, and one is gone" scenario can be.

If you're going to have an employee who performs "x" duties and those duties are essential, you need two employees who can do those things. With two, you're the boss, and you can, if and when the need occurs, be ruthless. With one, you're not a boss at all. You're a hostage.

Recently, a friend of mine with a small business found her assistant/office manager stealing untold amounts of time. Because my friend had taken my advice and had two assistants/co-office managers working for her at the same time, she was able to fire the one who was shirking her duties. Had she not taken my advice, she'd have been held hostage at gunpoint by her own dysfunctional and thieving employee. You decide at whose head the gun is pointed.

Just as a bonus point, one's the worst number for anything else, too. Having too much of your revenue dependent on one key account, one product, one service, one advertising media, one calendar event, one means of distribution, one anything is just bad business.

On the marketing and business development side, it's important to remember that diversity equals stability. Entrepreneurs often confuse an invention, a product, even a website with a business. Whenever your money is coming to you funneled through just one thing, you're in mortal peril 24/7/365, no matter how rich you may be or feel.

A great business has diversity of success drivers in every aspect of the business. It has diverse sources and means of new customer acquisition, diverse means of monetizing those customers, a diverse portfolio of products and services, diversity in its distribution channels. The best businesses have equity in their control of their customers, not just in their products. Business owners and staffs tend to get lazy or cheap about this and let the diversification narrow, relying over time on fewer and fewer sources, methods, means, media, and distribution channels over time, letting success lull them into false sense of security.

The exact same thing occurs with the people in a business. Over time, more and more power and control of vital functions concentrates into fewer and fewer people's hands. In this way, power actually equalizes between the invested and at-risk owners and the hired hands. This is one of the seven deadly sins—sloth—insidiously permeating a business. Don't let it happen to you.