How to properly turn off REVISIONS and AUTOSAVE for whole site and optionally for a custom post type only

Question

Is there a hook/function combination that can be added to my theme's functions.php to properly disable REVISIONS and AUTOSAVE for the entire wordpress installation? What about if just for a certain custom post type? Searching online gives various hacks from deregistering scripts to tampering with core files. What's the acceptable/correct way to do this?

Answer 1

This should be placed in your wp-config.php (and no where else):

define( 'AUTOSAVE_INTERVAL', 60*60*60*24*365 ); // autosave 1x per year
define( 'EMPTY_TRASH_DAYS',  0 ); // zero days
define( 'WP_POST_REVISIONS', false ); // no revisions

Answer 2

I'm also looking for how to disable autosave. But here's what I was told in a Trac ticket:

If you really need this feature you should manage the sequential IDs yourself in a custom field and then implement custom URL routing. It shouldn't be too hard to pull that off.

Answer 3

This is how to modify autosave interval

And this is how to modify post revisions

So to use it in your theme, try to declare appropriate constants in your functions.php file.