A Feature by Adam Perry (Mogri)
If there's one aspect of your RPG that has the capacity to make or break the game's balance, it's the player's ability to heal. Healing can affect the game's entire style. Make it limited enough and your game becomes a survival romp: the player counts every HP lost. Make it free enough and the player is afraid of nothing. There are many ways to approach the subject of healing: how you do it will largely shape the game's overarching strategy.
Most RPGs favor healing either in battle or out of battle, but not both. A good example of favoring in-battle healing is Final Fantasy IX, which had abilities and items that provided better healing inside of battle. The player could still heal out of battle, but it was more expensive to do so. More commonly, RPGs favor out-of-battle healing. The standard way to do this is to make the basic Cure spell more cost-efficient than the higher-level Cure spells or to offer cheap potions that don't heal enough to use in battle.
Why would you ever motivate your player to heal inside of battles? Well, it creates an interesting choice for the player: when do you heal? It's cheaper in battle, but you're putting yourself at risk to do so. This is especially effective when resources are limited. The decision is more interesting when it makes more of a difference. This method puts the focus on the dungeon rather than the individual battles.
More commonly, though, you'll want to make healing more difficult inside of battles. This method puts the focus on each battle. You'll usually come into the battle at full HP, but if you need to heal during the battle, it'll cost you some heavy MP. The player is motivated to finish the battle quickly and move on.
In tandem with the previous consideration, let's think about revival. A common approach is to provide relatively inexpensive revival, but to make it much more expensive to revive an ally to full life. The more difficult games make revival harder to accomplish, though. In the NES version of Final Fantasy, it's impossible to revive an ally during battle and only possible outside of battle with a high-level spell or a trip back to town.
Balancing revival versus healing is not trivial. You'll want to provide a means of revival to the player early on so that an accidental death in a random encounter doesn't screw him over completely, but you don't want to make revival too inexpensive, either: if revival is cheap enough, there's not much incentive to heal wounded characters. Just wait for them to die and then revive them.
One way around this problem is to disallow revival during battle. This has serious implications on the rest of your battle design, though: suddenly instant death spells are a huge issue and characters that can die in one round of combat are too unreliable to be useful. An easier approach might be to fix the number of revival items that the player gets. I think it's Final Fantasy V that does this: Phoenix Downs can be found in dungeons and will drop randomly, but they can't be purchased. The Life spell is still somewhat expensive in the endgame and the full revive spell is one of the most expensive in the game.
Another approach might be to allow revival only during battle. The Life potion that brings someone back with 100 HP is great at the beginning of the game, but later on it becomes a struggle to keep newly-revived characteres alive -- those 100 HP don't stretch nearly as far. Instead of being able to wait until the battle's over to bring everyone back, suddenly death is a bigger deal. It becomes risky to finish a battle with only one hero left alive because you know you'll be starting the next battle in the same condition. This method works whether you're emphasizing in-battle or out-of-battle healing, with different implications for each.
Consider the following scenario: You're facing off against the vicious Red Dragon. He uses his breath attack, bringing your entire party to half life! Fortunately, your healer casts Cure4 on the entire party, bringing everybody back to full health.
Attacks that target your entire party aren't nearly as menacing if you're able to cure it all at once. Let's suppose that your healing spells can only target one character at a time. Suddenly you're looking at four turns to bring everyone back to health. That breath attack is much more menacing now, isn't it?
Healing the entire party should come at a much higher cost than healing just one member. For a much more difficult game, don't allow it at all. Of course, this has some broad implications: suddenly multitarget attacks are much more of a threat. Allowing a hero to revive all allies is generally a bad idea; this ability should be very expensive if it's included at all.
The times have changed in RPG land. It used to be that your party would need a healer. Nowadays, anyone can learn healing spells. This change has crept in subtly but is really a significant departure from the classical design. When everyone's a healer, there are no healers. The dedicated healer has been phased out of the mainstream RPG.
Consider Chrono Trigger, a game that sits on the fence of "everybody can heal." Only Lucca and Magus have no healing ability; Chrono and Ayla additionally have very little healing capacity. (Chrono learns Life, remember.) Because healing is so accessible by the end of the game, Marle is essentially useless. Aside from Life2 and Haste, everything she does can be done by someone else. Her offense is negligible and she can't even heal multiple targets.
Now consider Final Fantasy IX. Several of the characters have healing-ish abilities, like Quina's White Wind or Amarant's Aura, but there are really only two reliable healers: Eiko and Dagger. Because the other characters' healing is relatively restricted, the relative importance of these healers is increased.
If you feel that such a tight restriction would hinder your gameplay, consider restricting other aspects, then, such as multitarget healing, status removal, or revival. Suppose your game has two healers, one of whom can heal the entire party, while the other is the only character who can revive in battle. (Tactics Ogre uses a similar model, actually.) Giving all characters access to healing abilities distills the challenge of your game.
Of course, not everyone is trying to make an incredibly challenging game. That's fine. Different games tackle these issues differently. Many games revive dead heroes to 1 HP after each battle. Some games fully heal your heroes in between battles. Some games don't allow healing at all in any form.
Consider what style best complements the rest of your game. If you want to create tension, make healing very limited, with the player relying on his scant HP supply to carry him through. If you want to emphasize long-term planning, limit what the player can take with him into the dungeon. If you want to emphasize each battle, make healing easy or automatic between battles.
Choose well! How the player heals will determine how he plays the game.