2. Do you or don't you?

Just because you can afford a hired gun doesn't mean you need one.

"There's a perception out there that only companies in trouble go to consultants," says Alberto Torres, a principal at the consulting powerhouse McKinsey & Company. "In reality, the large majority of companies recognize the value in bringing in a third party that has objectivity and methodology and can look at a similar situation across multiple industries."

But just because you can bring in a consultant doesn't always mean you should. Like lawyers and doctors, consultants are experts in specific fields. They can reduce the risk involved with a major undertaking, but they're no substitute for employees. Assess your proposed project and determine whether adding more permanent staff is the solution. Also make sure you go with a consultant only when you need a new skill set. Don't duplicate the skills of existing employees. Otherwise you risk creating tension between consultants and the staffers they work with.

"When a bunch of outsiders descend on you, there is a vested interest in wanting to prove these outsiders don't know more than the insiders," says Glynn Evans, chief information officer at Esurance.com and former senior vice president of information systems at Reuters, who has worked with a variety of big-name consultants.

Once you've decided to hire a consultant, you need to do some soul searching. "You have to do enough of your own diagnosis before you get a consultant involved," says Roger Walters, CIO and vice president of consulting at Booz-Allen & Hamilton. "The No. 1 issue has to do with scope: Do you know what you are asking the consultant to do? How broad is the scope of the project?"

The more specific you are, the better. Telling a consultant, for example, that you want to grow your business is too broad an assignment. Do you want to open new branches, bring in more customers, expand globally, or overhaul your network?

When picking a consultant, you are choosing a business partner. You have to decide what that partner's role is: strategy, design, implementation, or all three. Some consultants will help you with a corporate strategy, for example, and then gracefully bow out. Others will create a strategy and then help you put it into action.