User blog comment:Lia Schiffer/ANIME SPECIAL: 268: Hatred and Jealousy, Orihime's Dilemma/@comment-1351982-20100504010122

season 1 are episodes 1-20, season 2 are episodes 21-41, season 3 are episodes 42-63, season 4 part 1 are episodes 64-79, season 4 part 2 are episodes 80 -91 and season 5(available for pre-order out June 8) are episodes 92-109. Basically the boxsets are the single discs with bonus material in box for a better value. Hope this helps. I am not saying go run out and buy every single dvd the day it comes out(I buy them all because I set them up for collectable reasons) but if there is an episode or a season you really like then buy it on dvd, itunes or where ever.