It happens to me every time.

I copy and paste it, log-in to Facebook and drop it in. I hit "Post." The link, image or whatever it is publishes. I wait a few moments, then scurry back to the news feed and eventually sign off. I come back later, waiting to see what my post has done on Facebook. How long will it live, and is it going to get many likes or comments?

Sound familiar?

A new study from Edgerank Checker suggests that the average lifetime for a Facebook Page post is only three hours. A post is considered "dead" when its engagement is less than 10% of the largest growth of engagement between hourly snapshots.

Posts are usually "alive" when they're in the Facebook news feed. If they're labeled as a "highlighted story," the posts receive even more interaction.

This data only applies to Facebook Page posts, however. Edgerank examined the lifespan of posts from individual Facebook pages, and found strikingly different results. Some posts on individual pages stayed "alive" for 10 hours, while others only lived for 15 minutes.

For this study, Edgerank collected data from December 2011 across 500+ pages and more than 30,000 individual posts.