It's been more than a year since I passed my Technician and General exams and obtained my license. If I were now to go for my Extra class license, would it simply be a matter of taking and passing the Extra exam, or would I need to pass the previous exams again? Under what circumstances is it necessary to "start from the beginning" in terms of testing?
I am in particular interested in the rules for the United States, but a broader treatment would certainly be more generally useful.