took about 2 hours- mostly sitting, waiting. bring a book (not in a purse or backpack- those are not allowed inside).
be sure to bring LONG FORM birth certificate (listing both parents' names).
i did have to go back to have my fingerprints re-taken, fortunately i lived nearby so it wasn't a huge headache.
it wasn't too bad, but it's not something i look forward to in the future either.