"Mario & Luigi RPG Brothers Fly Together!" "The story missions in " are a very unique kind of mission in the game. What you need to pay attention to when doing story missions is that only the red story missions are the most urgent. When you unlock the dungeon mission for the first time, you will be told what to do with some dungeon missions. It will expire if not completed in time.
What should you pay attention to when doing plot tasks
When you unlock dungeon quests for the first time, you will be told that some dungeon quests will expire if not completed in time. At first, you might think this means you need to complete all quests immediately, but there aren't actually that many that expire.
Instance quests that only have a flashing red icon are urgent and you'll know them when you see them, as they usually have some kind of story relevance. There are only a handful of them in the entire game, and I recommend completing them as soon as they appear, as they are usually more interesting and involved than regular quests.
These are the only tasks I would drop everything to do. Otherwise, you can safely ignore the quest until you want to change directions, or need additional items before continuing.
If you feel you are falling behind in level or equipment, there is an NPC on the ship-shaped island near the cannon who will evaluate you and tell you areas for improvement.