2008 vs 2009 vs 2010 schweser L1 notes

hi guys i’m writing L1 in june 2010. i got the 2008 schweser notes from a friend and have an option of buying the 2009 notes second hand. in your opinion, does the notes differ significantly over the years, ie, should i go through the trouble of purchasing the 2010 notes or will the 2009 or 2008 notes be sufficient? i intend to only use the notes. thanks