There are some quests that only appear once every 6 months or so, and there are some quests you can only complete successfully once. There are other quests that are pretty common and you'll see repeated a lot -- like the gathering branches quest.
When you don't complete a quest in time, it gets erased for the quest log, so I think that means there's a chance for it to show up again, even if it was an only once kind of quest. But I don't know for sure.
Topic: Does quest reappear if character left a village without asking how it is going? (Read 3003 times)