A friend who recently hired me to rewrite her résumé asked if I'd also look over her cover letter once she'd written it. Of course, I told her. But do you even need it? With computers scanning résumé​s for keywords, I wondered, and decided to do some unofficial research. I posted this question to my company Facebook page: "Are cover letters still a thing? Discuss."

"I think they are, because they are not. It's impressive to see a cover letter from an applicant because they are rare," wrote Willa Buchanan, a director at Benefit Communication Insourcing, a benefits communication firm. Many echoed Buchanan's sentiment and made their case for the cover letter; there were no dissenters.

"As an employer, if I get a résumé without a letter I throw it out!" wrote Sarah Baucom, co-founder of Girl Tribe Co., a women positive graphic T-shirt company that showcases women entrepreneurs with their traveling pop up shops called Girl Tribe Pop Up.

If you're hiring someone for a new job, I'm here to tell you: Take cover letters seriously. They indicate an applicant is going the extra mile, and can help differentiate résumé​s that seem all too similar without requiring you to hop on the phone with every single candidate.

If you're applying to jobs, I'm here to tell you: The cover letter is still a big deal to recruiters and hiring managers. Turns out, if you skip the cover letter, you might just get skipped over in your hunt for your next great job.

Kristal Kuykendall reported that the cover letter made all the difference in the search for her next job in journalism. Her method: Paste the cover letter into the body of the email to hiring managers and attach her résumé​.

"How else am I supposed to stand out, get them to click on my résumé​ PDF, when there are maybe dozens or more other applicants?" wrote Kuykendall, now the editor of a suburban Dallas newspaper. "My method seemed to work, for whatever reason. I'd say I received some form of contact or interest from about 12-15 percent of the companies I applied to, and had a dozen interviews, and got a fantastic job!"

If you're applying to a smaller company, a cover letter can show real gumption--even if you've already been corresponding directly and closely with your would-be boss. "It doesn't have to be super formal," added Girl Tribe's Baucom. "Just thoughtful and explains their skill set."

At companies with layers of people and machines between you and the hiring manager, cover letters can feel like a big waste of time. Sometimes, HR will extract just the résumé ​from the online application system, sending that to the hiring manager. You just need to work the system a bit.

One idea: Make one PDF with the résumé​ and cover letter all in one. In this case, I'd suggest placing the cover letter after the résumé​, because you want the scanners to pick up the résumé​ first. You'll also want to load up the top of your résumé​ with keywords that will be pleasing to the computer scanners.

The cover letter serves the same purpose as it always has, which is to dive deeper into your career and expertise than you can in a résumé​. It helps you tell your professional story and spell out why you're the perfect fit.

Instead of thinking of cover letters as wasted time, think of not writing them as wasted opportunity.