Like most places, our school has a set advising period. It started in mid-October when the department sends out messages, puts up posters, and supplies sign-up sheets for faculty members to put on their doors. After a couple of weeks, the department usually extends the "official advising period" and puts up more brightly colored and imposing posters ("IMPORTANT!").
I'm not sure why they bother, because advisees seem to come in two kinds: the ones who sign up the first day and come in bright and early in the advising period with a full slate of courses they need to take, and the others.
The others are just showing up now, once they've figured out that they can't register until they've seen an advisor. They're writing me slightly aggrieved notes:
"I came by to sign up for a time, but there weren't any time slots left. " (That's because the advising period ended two weeks ago, but never mind; I e-mailed the person back and set up a time.)
"I'm available these times [none of which intersect with any times I'm available.] Please e-mail me and let me know when we can meet." (I respond by telling the person when I'm available and leave him or her to figure it out.)
Somehow, it all works out. The stragglers usually have no idea what they want to take (what a coincidence!), so those appointments take longer, but they get the courses they need, or a close approximation. Then they depart, leaving behind them only the smell of Dayquil and cough drops (for all of them have vicious head colds, an added bonus when you're sitting next to them for half an hour being coughed on), ready to be surprised by the whole process again next spring.