I recently realized that some schools (e.g. Vanderbilt) allow students to send updates about new achievements or awards after their application is submitted, or even after they have been waitlisted. I know it probably varies from school to school, but what is the general rule on this? Does it range a lot depending on the school, or do pretty much all schools accept continuous updates?
You can always update any school. And it is particularly important to provide updates to those who have been waitlisted. Many schools protect their yield and waitlist those they suspect don’t really want to attend. These are schools that tend to be student safeties. So when they get an application with scores and grades significantly better than students usually attracted to the school they wait list them and then look for signs they want to get off the waiting list. That way they don’t waste an acceptance on someone unlikely to come. Updates with continued messages of interest-and even a promise to attend if you get an offer (if true) can help.