The fact of the matter is, people are spending less time with companies than they did in previous generations—and it’s not because of a lack of work ethic, just because they can or they want to experience other opportunities. On average, employees in the younger generations stay in a job for 3 years or less, so you want to do everything you can to keep them as long as you can.
Lacking a fully staffed workforce is one of the fastest ways to drive employees away, so it benefits you and your permanent employees to utilize supplemental labor.