If an employee has quit but you really want to keep that person, should you make a counter offer? Probably not. The reality is that when your employee starts looking for a new job, you've already lost him/her, and it's (usually) not about the money. Instead of focusing on keeping that person, look at your remaining employees to make sure you're paying them a good, solid, market rate (and if possible a bit higher). That way, you lower the chances of this happening again.