Earlier, Google has double its characters limits from 160 to 320. It has been rolled back to 160 characters which can be seen in Google SERP.
Meta Description does not play any role in SEO and its not a ranking factors.
But it provides an overview of what the content is meant for.
A well written Meta description can increase CTR which in turn can improve the ranking against the keywords.
When it has been rolled Back?
It was rollback in third week of May, 2018. As a result, now Google SERP has 160 characters meta description.
Things to keep in Mind for Meta Description:
1- It should be unique i.e. Duplicate meta description does not get reflected in SERP. In a case like that, Google pulls the meta description from the Content.
2- It should entice the Users to Click i.e should reflect or fulfill the searchers goals.
3- Character limit has been reduced to 160.
4- Structure data makes user entice to click. Like in a case if you had Products and reflecting its price & reviews in SERP.