So basically

<p>A person with the third registration window can have all of the class sorting done already, and a person with the 1st window can do it in say, two weeks....and the person with the first window registers for classes b4 the other person despite putting the classes in later? like the classes dont "fill up" in the bookbags when you do them, right?</p>

<p>No, it doesn't matter when you do the pre-registration stuff as long as you do it by the specified date(June 29th).</p>

<p>yep. it doesn't matter when you put them in, it just matters when your specified registration date is.</p>

<p>I don't get the June 29th thing. I'm third window as well, so can I go in and change my primary bookbag around the day before I register (so as to eliminate the classes that are full and add classes with space so I can get registration done as efficiently as possible)? If so, is the June 29th deadline just for answering the questions and not for class choice?</p>

<p>right.
it's 100% recommended to be checking aces regularly, especially if you are the third registration window. you're going to need to register (not be on waitlist) for 4 classes going into freshman year (after that, there's more leeway with waitlists) so you probably will have to rearrange anywhere from 1 class to an entire schedule between the first window and when you enroll. you want an easy morning on the third window, and hopes that when you hit enroll all you're getting all four classes.</p>

<p>do everything by the deadlines though -- i remember you have to answer a lot of questions on aces before you start (this sorts you with pre-major advisers i believe, unless they've changed that) and i want to say that without talking to a dean and getting executive power, if you don't do this step, you may not be able to enroll at your designated time.</p>