Both are limited with a certain number of characters to use.
Most of all it is important to have your keyword on the title and description; short but descriptive.
Title and description must be able to tell what the site/page is about.
Based on Google SERPs, title tag and meta description character limits have decreased 21% and 23%, respectively. Now it is 55 characters (including spaces) for title tags and 115 characters (including spaces) for meta descriptions.