Got all fragments twice in XIII-2, and am currently considering quitting my XIII playthrough due to having gotten to a place where I need to farm to keep up.
Unless you're doing a challenge run or working on Treasure Hunter, I guarantee that farming is not necessary. Improving your strategy will suffice. Drop on by the FFXIII board if you want tips or advice.
Thing is I managed to play the game fairly well, up to the point where I didn't have to upgrade any weapons and could skip most of the enemies since I could use strategy to defeat the bosses anyway. Thing is my characters are now so under-leveled they'd die after most any strong attack.
I can progress just fine, but it takes the fun out of the gameplay when I need to stop to heal during Staggers.
http://24.media.tumblr.com/tumblr_m2xlrawEt51qajc4eo2_500.gif I DON'T REMEMBER THIS PART