I did already have the earlier seasons on DVD, so I debated whether it was worth getting duplicates, but it really does work out *ridiculously* cheaper to buy the box set. I would have been spending more than £20 each on buying seasons 8 and 9, whereas I picked up the entire 1-9 box set for less than £50! And I suppose I can justify buying the earlier seasons twice as it is replacing DVDs with Blu-Ray's