Maybe not months unless you decide to replay it. It took me 1 month and a half for a 100%, but I used a guide on only the heart pieces. It should keep ya hooked for a good time. It's kind of hard though. The lack of dungeons is made up for numerous side quests.
Thanks. Oh dont worry about that. ;p Just as long as there is quite allot to do in that game, it should be enough to keep me hooked for weeks or even months ;p