Establishing a great company culture is a neverending process, which makes it difficult to measure just how well you're doing. 

Entrepreneur Norm Brodsky, who has started seven business, believes the key is to simplify. In evaluating the culture of his own companies, he chose one key metric to on which to grade himself: retention. 

"You have to pay decent wages. That's one thing. But when you have a warm, nurturing culture … they're going to stay with you," Brodsky says. He adds that at one of his companies, three top employees stuck around for 30 years, while 16 others stayed for about 18 years.

In addition to how successful you are at holding on to your employees, a related metric is customer retention, Brodsky says. If your employees are satisfied, your customers will know based on their ongoing interactions with your staff.

Keep this in mind when you're deciding who to let into your company, Brodsky says. 

"Hire for attitude not for skill. Skill can be taught," he advises. "And that's the surest thing that you can do."

For more on how to sustain a positive company culture, watch the video below.