Empty Trash

Default: 30 days

Define number of days to keep before trashing:

define ('EMPTY_TRASH_DAYS', 7);

Disable trash:

define ('EMPTY_TRASH_DAYS', 0);

Reduce Post Revisions

Define number of kept revisions:

define( 'WP_POST_REVISIONS', 3 );

Disable revisions:

define( 'WP_POST_REVISIONS', false );