It's a miracle I was able to play through KOTOR 5 times. Usually, I don't even FINISH games. Especially cRPG games. As soon as I get to the end levels and the "story" has been revealed, I get bored if all that's left is the end fight.
For me, if it's an interesting story, I can probably play through 3 times. The first time I usually rush through, missing stuff. The second time I take more time and do things (side quests, talk to all NPCs) that I missed in the first run through. The third time is to exhaust all possible things to do. In KOTOR, I was able to play through an additional 2 times, probably because of the LS/DS ending and the male/female romances and whatnot. But after all that, I can't keep interested when I can literally play out each area in my head to 100% accuracy.
Fan made mods helped a bit. Adding different robes and new powers were a "novelty" that helped me play through more times. But as a whole, once all things have been tried and exhausted, I move on.