I started it in infantry school when I was in the Marines. He had 5 or 6 books out at the time, but it was taking about a year and a half between books at the time, so I would reread the whole series prior to reading the new one. After a few iterations, I gave up on that strategy and decided to wait until he was finished. He was planning on writing 12, and made it through 11 before he was diagnosed with cancer. He brought in Brandon Sanderson, who is a great author in his own right, to finish off the series. Sanderson couldn't do it in one book and had to write three to conclude it. So, with one prequel, there are 15 books in total. That ended up being almost 12,000 pages. The audiobooks of the series have a 19 day, 5 hours and 25 minute run time.