<p>i know that they prefer to have the common app by December 1, but it's still ok if i just turn in everything by jan 1, right?</p>
<p>Absolutely! The only reason they give December 1 as a "Priority Deadline" is because that's when they start reading applications (I think). Sending it after December 1 but before/on January 1st should not affect your applications negatively.</p>