Cache Lifespan
The Cache Lifespan feature in the Advanced Rules tab will set the maximum age a cached page can be.
In WP Rocket versions before 3.16, the Cache Lifespan feature can be found in the Cache tab (deprecated).
How does it work?
WP Rocket will check the cache files' creation every hour. If at any of those hourly checks, WP Rocket detects that a cache file is "older" than the current Cache Lifespan value, then WP Rocket will delete it, and re-create it afterwards if the Preload is enabled.
The cache files that are removed after the Cache Lifespan check are the ones located at /wp-content/cache/wp-rocket/yourdomain.com/.
However, these actions don't apply for the minified files located at the /wp-content/cache/min/1/ folder.
Which value should I use?
Heads up: The Cache Lifespan just can be set globally affecting all of your pages. It can't be set on specific pages with different values.
Technical notes
- Cache Lifespan feature will not work on hosting platforms where WP Rocket caching is disabled, such as WP Engine, Kinsta, WordPress.com, etc. For the full list check Hosting Compatibility article.
- The hourly check is done using a cron job named rocket_purge_time_event.
An admin notice regarding a Scheduled Cache Purge failed task can appear when:
- The cron task runs out of schedule due to a long queue of other cron tasks or WP Cron not being triggered. However, the event should run at later time. This should be treated as a false positive warning.
- WP Cron is not working properly. See more.
When to use this feature
A common example of when the Cache Lifespan feature is useful is when there's a widget on most or every page of your site and you want to refresh its content every given hours.
Note: Using a very short Cache Lifespan can cause CPU overload due to very frequent cache files generation when WP Rocket's Preload is enabled. If you need to refresh a page's content very frequently we recommend using a cron job, and set a higher Cache Lifespan value for your site in general.
Also, if you're managing a website which content only require updates on a monthly or yearly basis - basically static websites - you could set a Cache Lifespan value of several days.