Best Practice SEO dictates that you need good meta information as it is essential for SEO. Two tags to focus on are title tags and meta descriptions. Make sure they are descriptive and most importantly, relevant to the content on the website.
If you do have duplicate meta descriptions on your website, you will most likely get a warning in Google Webmaster Tools. Take this as a gentle nudge towards getting into the good habit of having a unique description for each page. After all, this is the summary snippet underneath your link on the search engine results page. The rule of thumb is to keep these under 150 characters in order to have the full sentence visible on the SERP.