You have a great team. Employees show up to work on time, deadlines are met and customers and vendors are happy. Then, the unthinkable happens – your best employee gives their notice. How could this happen!?

Unfortunately, it’s more common than you think. CareerBuilder found that while 59 percent of workers are generally satisfied at work, one in five said they plan to change jobs this year or next. One in five is a staggering figure, but what’s worse is that just 10 percent of employees surveyed said there was someone internally who could step in to fill their role if they abruptly left their employer, according to a study from the staffing firm Robert Half Management Resources.

The importance of a succession plan is a discussion for a different day, but the hope is that your best employees won’t leave your company. To help make sure that happens as little as possible, read on for the top four reasons employees choose to move on.

Your Employees Are Overworked

According to an article at INC42, “new research from Stanford shows that productivity per hour declines sharply when the workweek exceeds 50 hours, and productivity drops off so much after 55 hours that you don’t get anything out of working more.” Remember to respect your employees’ time and if you do need more from them, show your appreciation through raises, promotions and title changes.

Your Employees Don’t Feel You Respect Their Personal Time

First Round Review talks about the need to understand that employees have lives outside of work. The article stresses that “from 5 p.m. on Friday to 9 a.m. on Monday should be people's own time, not the company's.” Certainly things will come up that need to get done between those hours, but if you show your employees you respect their time, they’ll show up to work on a day off from time to time to ensure deadlines are met and customers are happy.

Your Employees Don’t See a Future

The best employees will be working toward a fulfilled career, so if they don’t see a future within your company, they’ll be gone before you know it. Make sure to schedule performance reviews and help your employees understand what opportunities are available to them to advance within the company, and what they need to do to get there.

Your Employees Don’t like Their Manager

This can go one of two ways. Either employees feel their managers micromanage and therefore they have very little decision-making power. Or, employees have difficulty even finding and connecting with their manager, and therefore can’t ask for important feedback to make for a successful working relationship. Managers should be present and available but give their employees the flexibility to make some decisions as appropriate, so that they feel their opinions and instincts are valued.

Even if you’re the best manager and feel you go above and beyond in each of the situations discussed above, good employees are still going to quit to follow their passion or lifestyle change. In the event that your employee unexpectedly quits, be sure to do an exit interview to better understand why and what you could’ve done so that you’ll be prepared for the next person in the role.

Now let's look at ways to keep employees both happy and healthy.