Does it affect rankings?
Not directly. Google has said meta descriptions aren't a ranking factor. They matter because a clear, relevant description can persuade more people to click your result, and more clicks from the same ranking means more traffic.
Why Google sometimes ignores it
Google often writes its own snippet from the page's content when it thinks that matches the search better than your description. Descriptions that closely match the page and the likely search are more likely to be used.
How long it should be
There's no official limit, but search results cut off long descriptions, usually somewhere around 150 to 160 characters on desktop and less on mobile. Put the most important words first so the message survives if it's shortened.
Why Meta Description matters
Your title and description are your ad in the search results. Two pages ranking side by side can get very different click rates depending on how clearly their snippets answer the searcher's question.
From vague to specific
'Welcome to our website. We offer many great services for your needs.' tells a searcher nothing. 'Emergency plumber in Tampa, available 24/7. Upfront pricing, licensed techs, most calls answered in under 10 minutes.' tells them exactly why to click, assuming every claim is true.
Common mistakes
Duplicate descriptions
Using the same description on many pages makes them look identical in search results and gives Google little reason to show them.
Stuffing keywords
A list of keywords reads like spam and rarely earns clicks. Write a sentence a person would actually want to read.
Promising what the page doesn't deliver
Clickbait descriptions raise clicks and then bounces. Match the description to what the page actually offers.
Leaving it blank
Without one, Google pulls text from the page, which may not be the part you'd choose. Write descriptions for your most important pages at least.
Where we work on this