Before getting braces

What has to happen before you actually can get your braces on?
I've read that someone got their braces the same day as their initial consultation with the orthodontist, but often it can take a couple of months because of the things that have to be done beforehand. If you have a good ortho, they'll make sure you've had a teeth cleaning recently, that you get a periodontal checkup (to make sure your gums are healthy enough to deal with the braces) and a general dental checkup for cavities etc. If you still have your wisdom teeth, they'll probably send you to the oral surgeon for a consult as well, to see how your wisdom teeth are doing and to decide whether they should stay in or come out. And then, if you have a cavity or an issue with your gums or whatever, that has to be taken care of before you can get the braces on.

What specifically had to be taken care of, before I could get my braces?
Two small cavities had to be filled.
Gums: There was a little flap of gum tissue that had to be cut away, otherwise, my gums were healthy.
Wisdom teeth: I only had two at this point (the other two had been taken out when I was still in my teens). One is impacted and will stay there unless it begins to move, because the danger of damaging a nerve would be to big when taking it out. The other one already had a large filling, and it didn't have the opposite tooth to work with, so it was not really functional. Within a few years it would probably have had to be taken out anyway (or needed a crown, but why do that for a non-functional tooth?)), so the recommendation was to take it out and I decided on going with that.