Potions allow you to recover hit points and mana without having to stop to rest. Some potions will recover mana or hit points over time while others will instantly recover them. However, there is a cooldown when a potion is used, so you must choose carefully what type and quality of potion you wish to use at what time. The exception to this is the Abyss potions the Contribution vendors sell. The potions have their own cooldown, while normal potions are on a 1 minute cooldown timer the Abyss potions have a 5 minute cooldown. This means you can use a regular potion and an Abyss potion if you are in need of quick recovery.
There are two other types of potions as well. While these potions also share the same cooldowns with the others, they have a separate purpose. The first are the curing potions, which allow you to remove abnormal conditions that have been applied to your character such as poisons. The second type of potion allows you to restore your flight timer while you are flying. This allows you to continue aether gathering or travelling by flight when needed.