The vast majority of quests in the game are once-per-character. For this reason many people focus as much on the main story quests as possible to level up their first class, leaving more quests available for later classes. Of course, eventually these all run out. Thats when PotD, dungeons, roulettes, and Fates are really useful. With that said, the first time completion bonus on guildhests is actually available for each class. Every class also gets its own version of the hunting log. And the challenge log is repeatable weekly, giving you more replenishing exp bonuses to spread around. The few quests that are repeatable have a different icon so you can tell. Heres an example beast tribe quest you can repeat daily.