There are some rumors floating around about admission being easier on students who submit their applications early, despite the fact that we have no early decision or early action at UVa.
While I think it's smart to submit in advance of the deadline, just in case there's some sort of glitch, you shouldn't feel pressured to submit your application right now if you haven't put the finishing touches on it. There IS an advantage to early submission, but it isn't related to the admit rate, it's related to your status page.
A few days after you submit your application, you'll get an email instructing you to log into our Student Information System (SIS). When you log into your SIS account, you'll see a to-do list for your application (and later, one from the financial aid folks). If you and your school officials submit items early and the chances are that your supporting credentials will be checked in more quickly and you'll see changes in your to-do list. By mid-December, the amount of items arriving in our office on a daily basis skyrockets and we can't check everything in on the day it arrives. So, you might wait weeks to see updates on your to-do list.
Now, there's no reason to worry about your to-do list until the end of January, but if you're the type to stare at your to-do list and worry, see if you can get some things in early.
Please don't call our office freaking out the first time your log into the SIS and see your status page. Give us until the end of January to get everything checked in. You won't be in trouble if school forms aren't checked until a few weeks after deadline. Your part of the application is what must be submitted by the January 1st deadline.