I have a huge vocal performance coming up, how long do I vocal rest?

Is your voice sounding fatigued or hoarse in anyway? If your throat is okay, no real vocal rest is necessary. You want to make sure you don't do anything like too much talking and of course, avoid yelling or doing anything else that could stress out your vocal cords. You should practice a bit every day just to keep your vocal cords warmed up. Don't avoid dairy unless it does bother you when you aren't singing as well. It's not all of the sudden going to give you phlegm if you it never has before. It won't hurt for you to avoid it, or anything else you fear MIGHT give you problems. Mainly, make sure you get enough rest for all of you. No partying or staying up too late. Eat enough healthy foods to keep up your strength but avoid stuffing yourself before the competition (don't let a large pizza crowd out your breathing room).

And try to relax! You know how bad tension is for a singer--goes right to the throat!

If you do have some serious hoarseness, take a couple of days and if it isn't better--go to a doctor in case you've really inflammed or damaged your vocal cords overdoing it in some way. Hopefully you don't have any colds or allergies to contend with.