phpMyFAQ

The "Time To Live" (TTL) is the configured for each website domain and indicates when the local web browser should check for new updates to a webpage. Usually the TTL is set for 1 hour to 1 day.

When a visitor browses your website, you only want them to have to download each page once. Page content is download and cached on the local machine where it is accessed until the TLL expires. If the user bounces back and forth between pages, you want them to get fast results so you do NOT want the TTL too low. In addition, the web host is not going to want any unnecessary access requests and will suggest that the TTL not be set too low.

On the other hand, if the TTL is too high, changes to the website will not be seen by users until the TTL expires for the given page. The user can always manually press "Refresh" in the browswer to force a check for updates, but many users do not do this. They just assume that they are always getting the most up-to-date content, which is not necessarily the case based on the TTL setting.

Another detail that may be important is that if your website contains Flash graphics and updates to the website are made while the user has the site open, pressing "refresh" usually does NOT download the new content. The user would have to close the browser and reopen. There is really no way to get around this and it is a rather isolated risk.