Google's John Mueller said that while it is useful for site owners to add meta descriptions to their web pages, it is "definitely not a requirement," he added. The usefulness comes from sometimes writing a meta description, "helps you to figure out a clear focus for a page," John wrote on Reddit.
John Mueller wrote on Reddit:
Yes, but also, there's no penalty to writing your own, and sometimes it helps you to figure out a clear focus for a page. Overall, I think it's still worthwhile to do so for individual pages that you care about, but it's definitely not a requirement.
Now, in 2018, John said that it is best to fill in your meta descriptions, Google even added examples of good meta descriptions in its help documentation. However, a study in 2018 showed Google rarely used your meta descriptions and even Matt Cutts in 2013 said he didn't write meta descriptions.
Most CMS platforms give you a quick way to add meta descriptions or automate the whole process anyway.
Forum discussion at Reddit.
