Figuring out the “stealth rolling” circumstances (which could be about admissions or merit) is really where almost all the “fun” is.
Sometimes they basically tell you, which is nice. Sometimes there are reliable reports of pre-deadline offers, which is also pretty definitive. Absent that, eh, hard to know.
I will note I have heard more than once that AOs can sometimes see when you STARTED an application to their college. If you start it well in advance but hit submit right before the deadline, supposedly that’s not an issue. But if you don’t actually start it until very close to the deadline, they supposedly might see that as a possible red flag in terms of actual interest. I don’t really know how to verify that, but it sounds plausible enough to keep in mind.