I had my general license for the past two years, it and the tech were not too hard to pass with a little studying. I tried the extra after I passed my general. It might as well been in Greek since I had no idea what some of the questions were asking. I bought the ARRL guide and it was no help. I wanted to have some understanding of what the questions were asking versus rote memorization of the answers. I won the ARRL auction for a two year membership to Hamtestonline.com, I think it was $38 or so. The site is set up so you can choose to study by answering the specific section questions or go though the entire course. You can also take simulated exams. If you miss a question, the site will insert it back in to the question pool until you answer it correctly enough times. The site also has a feature to show you the applicable formulas and also to show you how to work the math problems. I appreciated that feature as I wanted to learn how to solve the problems. It also tells you if there are only two questions from that section and just to memorize the answers if you want to save time. I studies for about 10 hours over several weeks and passed my extra with ease. The site really facilitated my understanding of the extra exam questions.