As a manager, one of your objectives is to staff your office with the most knowledgeable and talented employees. An important related one is to motivate those employees to share their wisdom and skills with the rest of the office.

If you hire someone who is an expert at sales, you benefit during their tenure at your company, but once they leave--either for a new job or to retire--you will find yourself back at square one. What if you could persuade that star salesperson to educate the other employees on the team? That would increase the benefits of having the expert employee exponentially.

The problem, as Harvard Business School professor Dorothy Leonard writes in Harvard Business Review, is that most employees have zero incentive to share their wisdom.

It may be an ego thing or they may want to get more money out of it, but they're probably not going to give of their own free will. They may ask to be paid as a consultant to train other employees. Or they may be frustrated with the company and flat-out refuse to help. This is a huge detriment to the business.

"If such knowledge leaves with retirees, it may be lost for good," Leonard writes. "In our research on knowledge transfer, we have seen companies greatly disadvantaged, if not crippled, by knowledge loss. Organizations cannot afford to lose these deep smarts."

That's why you'll want to put in the extra effort to get your employees to share their knowledge. If they're looking for extra pay for their services, make sure that you don't just hire back retirees to do the same old job. If you are going to pay them to return as a consultant, hire them to train other employees instead of doing the same work on their own. GE's Global Research Centers, for instance, hire back retirees to be mentors and teach junior employees. They also implemented a knowledge transfer program for current employees.

Sometimes, though, it's not just about the extra money. Your employee may feel that if he teaches others he will no longer be the go-to expert. He may fear he will lose part of his identity and stature. This is why you need to start early and initiate a knowledge-sharing program before you get to this stage. Maybe that means not promoting employees until they have mentored their successor. Maybe you determine compensation based on a team's performance as opposed to an individual's. Whatever the policy you choose, try to instill sharing and interaction as a part of the company culture so that it only makes sense for employees to share their wisdom.

The toughest challenge of all in terms of convincing employees to share their wisdom is when an employee is frustrated with the company. Here too you will need to start early. Look out for resentful employees and make sure they feel valued at the company. Acknowledge their work and provide positive feedback. This will foster better feelings toward the company and enable a philosophy of "paying back" and "leaving a legacy."

Whatever the reason may be for employees' refusal to share knowledge, you owe it to your company to challenge them and change their mind. "The capability to transfer deep smarts from experts to their successors, as one manager we worked with recently observed, is not just 'nice to have,' but an 'absolute need to have,'" Leonard writes. "Hoarding knowledge is a luxury that no organization can afford."