WordPress automatically saves revisions to your posts and pages every 60 seconds. You are able to modify decrease the time interval if you’d like to reduce the chance of losing changes or increase it to cut down on the load to your database.

You can change the autosave frequency by adding the one of the following lines to the site’s wp-config.php file.

Examples:

/* Set AutoSave to 30 Seconds */
define ('AUTOSAVE_INTERVAL', 30); 

/* Set AutoSave to 5 Minutes */
define ('AUTOSAVE_INTERVAL', 300); 

Whenever you modify a post or page on your WordPress site, a copy of is saved to make it possible to revert any changes that have been made.  Although this is a great feature when you quickly need to revert site content, the number of revisions can quickly add up and begin to take up a large amount of space in your database.  It is possible to set a maximum number of revisions that will be saved for each post/page by adding the following snippet to wp-config.php

Examples:

/* keep a maximum of 5 revisions for each post/page */
define('WP_POST_REVISIONS', 5);

/* disable revisions for post/pages */
define('WP_POST_REVISIONS', 9);

Ever since the release of version 2.9 WordPress automatically deletes posts, pages, attachments, and comments, from the trash bin every 30 days. You are able to change this default behaviour by adding a snippet of code to the wp-config.php file of your WordPress install. This can be handy if you want to empty the trash more often to save space, or if you want to disable the trash altogether.

The following snippet would empty the trash every 7 days. You can set this to whatever number works best for you or even 0 to disable the trash feature completely.

Example:

define('EMPTY_TRASH_DAYS', 7 );