Parents and students, haunted by college admission deadlines, ask wonderful questions about what deadlines actually mean. For example, does November 1 mean that the application needs to be at the college by Oct 31? The answer is that students can actually hit the "send" button on their computer to send applications to a college with a November 1 deadline on November 1. However, it is best to try to send applications the day before or early on the day that they are due in case of unexpected things like power outages and website issues.
Another great question is whether all supporting documents like high school transcripts and SAT scores need to be received by a college by the admission application due date. The answer is that it depends on the college. The University of Virginia, for example, has a November 1 deadline for early applications but allows school counselors until November 10 to get official transcripts and letters of recommendations sent. Other colleges, want everything by the deadline or give counselors even more time to get documents in.
Read the admissions page of your college website carefully for deadline and checklist information to be clear about what is due when. Set up a to-do list for yourself to make sure you give your counselor, test score entities and your recommenders time to get your documents to your colleges in time to meet their deadlines.