SP is a valuable commodity in Persona 5. It is required to cast magic, and without magic you are vulnerable to most enemies.
Heading into a palace or Mementos, you should be very careful about spending your SP. Especially later on once magic becomes most costly to cast, it's very easy to run out of SP, resulting in pressure for you to head back into the "real world" earlier than you would like. Due to this, you will want to maximize the effectiveness of each magic cast by exploiting weaknesses whenever possible. This may entail bringing your least favorite party member with you just because he or she has access to a school of magic that is effective in a particular dungeon.
However, there are a few ways to restore SP, such as:
- Accessories: There are accessories purchasable at the Clinic that restore SP. Though, these are very expensive starting at 40,000 Yen, and require you to have your Death confidant (Takemi) at high enough of a level.
- Coffee: After speaking with Shinjiro enough times you will earn him as a confidant. When this happens, you will be able to make your own coffee in Cafe Leblanc, which takes up a time slot during your afternoon or evening. Coffee restores 30 SP.
- Treasure: SP recovery items can be found as treasure and drops in palaces and Mementos.
- Vending Machines: A small number of vending machines sell SP recovery items, namely the vending machines near the Bathhouse, Arcade, and outside Shujin Academy.
Good luck!
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