How to limit post revisions

Having unlimited saves of post changes can clutter your database and slow down the website performance

Find the wp-config.php file in the root wordpress folder
Adding the line

define( 'WP_POST_REVISIONS', 3 );

will limit the post revisions to 3 (plus 1 autosave).
-1 is to keep all and 0 is for none
(except the autosave)