Hiring the wrong employee is more common than one might think, and is it equally expensive.

Three in four employers have made a bad hire, according to a survey from CareerBuilder. The average cost of making the wrong choice on an employee is close to $15,000, and losing a good employee costs nearly $30,000. Conducted through Harris Poll, the company surveyed 2,257 full-time hiring managers and human resource professionals and 3,697 full-time workers.

Two in three workers say they have accepted a job and, soon after realizing it was a bad fit, more than half of these workers have quit within six months. Forty-six percent said they realized they were in the wrong job because of toxic work culture, while 40 percent blamed their boss’ management style and 37 percent said the job didn’t match the initial listing.

Bad hires can lead to a ripple, as poor performers lower the bar for other workers on their teams, and their bad habits spread throughout the organization. Thirty-seven percent of employers said a bad hire had caused less productivity in their workplace in the past year, while 32 percent said they lost time to recruit and train a new worker, and 31 percent said the quality of work was compromised in their office.

A survey from staffing company Robert Half found that while most managers notice within a month that they have made a bad hire, it takes an average of nearly nine weeks to let the person go.

Strong onboarding processes can improve new-hire retention rates by 82 percent, according to the Society for Human Resource Management. Businesses with weak onboarding programs are more likely to lose people within the first year.

Here are five basics to improve your odds of securing a stellar hire:

Go with your gut

Put more trust in your instincts. That’s easy to say but difficult to do when you’re filling a critical position, and everyone has advice to share. Red flags always mean something.

Check references

Check and double check every candidates’ references. References are invaluable free resources that prevent costly mistakes.

Add a third-party perspective.

Bringing in a third party perspective such as a seasoned advisor or an employee from another function can help add valuable perspective.

Take a test drive

Structure your interview process so its representative of the actual scenarios this person would need to succeed in.   Another option is setting up a trial period so the candidate can start working with the team for up to 30 days before converting to full-time. This allows both sides to evaluate the fit and give a good sense of what the longer term partnership would look like.

Set clear expectations

Discuss role, responsibilities, and set clear expectations for all new hires in their first week. Then, if the expectations aren’t met, there are no surprises on either side.

Nearly every CEO will make a bad hire in his or her life, and there’s no formula to ensure every new employee is a great one. But when you take new employee recruitment seriously, hire carefully and fire quickly, you’ll get it right more often than not.