I know several people who are in the process of changing jobs. All of them are moving on to what seems like great opportunities for them, but they leave an incredible hole in the life of their current employer.
It takes a long time to find someone to just do the job that is vacated. It takes even longer to find someone to know the job. The nuances of how the job is done, what is important/what isn’t, details that only the person doing the job knows – a lot of knowledge walks out the door when an employee leaves.
My dissertation studied the importance of employee training and development and at my defense, I was asked how I would pay for it. My answer was that it was cheaper to keep someone than to replace them. It is estimated that it costs $2000 just to replace a fast food worker. Imagine what the loss is for a professional.
Sometimes employees leave for great reasons and you should support their move. But many times employees leave in part because you haven’t done enough to challenge or support them. It’s a delicate balance to provide new opportunities and maintain a reasonable workload and it requires continual attention and feedback.
Yes, it takes a lot of time to be a great supervisor but work as hard to keep your stars as you will have to do to fully replace them.