WordPress has WP-Cron which is a built-in system used for scheduling time-based tasks. WordPress core adds a number of default cron events and those can easily be modified using a plugin such as WP Crontrol. After you have installed and activated the plugin it will add sub-menu items to; Tools > Cron Events To view, all WordPress core events go to the middle section which will show all of those. Two cron events that are worth modifying would be; delete_expired_transients The delete expired transients cron event normally runs daily to delete transients in the options database table that have expired