There are 297 main story quest. So at 10 a day, that would be around 30 days for MSQ alone. Side quest wise, not counting raid content, class/job, and beast tribe quest, you're looking at around 1110 side quest. So everything together, without cutscenes, would take roughly 16 weeks. So close to 4 months. That's if you do 10 a day. I quess watching all the cutscenes would just add a couple hours on to that.