In the original Dungeons & Dragons game, ordinary monster attacks inflicted just 1d6 damage. Yet characters still died, frequently. Clerics gained far fewer spells and much less healing than today, so most damage took a trip out of the dungeon to heal. Heroes mounted dungeon expeditions, fought as many battles as they dared, and then hoped their mapper could lead them to safety and healing.
To threaten full-strength characters in a climactic fight, monsters needed unique attacks that did massive damage, like a dragon’s breath weapon, or save-or-die effects like a beholder’s eye rays.
Advanced Dungeons & Dragons granted clerics more healing spells, so characters entered more fights at full hit points, but damage still taxed resources that only a rest could regain. If the cleric squandered spells on something other than cures, the party hollered.
Third edition changed that equation. Without anyone ever needing to rest for spells or healing, characters could regain all their hit points after every fight.
A 2nd-level character who had gained the 900gp of treasure recommended in the Dungeon Master’s Guide could buy a 50-charge Wand of Cure Light Wounds for 750gp. At 2nd level, the party might share the cost. In just a few levels, characters gained enough gold to make buying in bulk a minor expense. Of course, dungeon masters could limit the purchase, but by 5th level, PCs stopped needing a magic shop. A cleric could take the Craft Wands feat and make wands at half price.
Third edition’s Living Greyhawk organized-play campaign enabled PCs to craft and purchase healing wands. Most characters bought Wands of Cure Light Wounds and loaned them to the party cleric for healing between battles.
In a standard third-edition campaign, savvy characters stopped needing rest to recover hit points.
Third edition’s designers probably overlooked how the low cost of healing wands would erase D&D’s 25-year-old limits on hit points and healing. The fourth-edition designers noticed. Their edition kept magic healing available for purchase, but also limited healing between rests. Rested characters gained a limited number of healing surges, and then healing magic let characters trade surges for healing. For example, healing potions just let characters spend a surge in the heat of battle. Fourth edition’s treatment of hit points and healing ranks as one of the edition’s best innovations.
At a glance, fifth edition seemed to keep D&D’s tradition of limiting hit points and healing between rests. This presumed limit made the introduction of the spell Healing Spirit seem like a game breaker. With a mere 2nd-level spell, everyone in the party could regain 10d6 hit points in just 1 minute. Casting at higher levels increases the healing, so a 3rd-level spirit could restore 20d6 to every PC in the party.
Blogger Merric Blackman summarized the concerns, “One of the major objections to the healing spirit spell is that it turns all the assumptions of hit point recovery in 5E on their head; suddenly we’re in a 3E-style game of ‘hit point loss isn’t important’ rather than the 5E-style of ‘hit point lost drains resources.’”
While Healing Spirit outshines other out-of-combat healing spells so much that druids need sunscreen, the spell doesn’t shatter any standing limits on healing. When the Player’s Handbook offered healing potions for sale for 50gp, the fifth-edition rules freed characters of any need to rest for healing or hit points. Unlike in early D&D, characters can buy potions. Unlike in fourth edition, potions work without a limit imposed by healing surges. Characters who gain a typical amount of treasure can easily afford all the potions they need. Most PCs gain tons of gold and have nowhere else to spend it.
Savvy characters can recover hit points without ever resting.
Dungeon masters who want to capture D&D’s original limits on hit points and healing between rests need to limit both healing potions and Healing Spirit. Such limits restore hit points and healing as a resource to manage through an adventuring day.
If you want to keep healing potions readily available for 50gp each, I suggest adopting a version of the fourth-edition limit: Drinking a potion lets characters spend a Hit Die for healing as if they had rested. To avoid doses that just heal a point or two, make potions heal an extra 1d4 hit points per Hit Die spent. Stronger potions spend more Hit Dice. With this house rule, make stronger healing potions for sale at higher prices. Although these potions spend hit dice, they still bring the advantage of granting healing in the heat of battle.
Potions of Greater Healing, Superior Healing, and Supreme Healing can remain unchanged as long as they keep their rarity and only appear in treasure. These potions bring the precious advantage of healing without costing Hit Dice.
James Haeck listed a couple of house rules for limited Healing Spirit. For instance, designer Jeremy Crawford suggests having the spell end once it restores hit points a number of times equal to twice the caster’s spellcasting ability modifier.
Of course, none of these house rules apply to organized play. Authors who write adventures for the Adventurers League should expect characters to enter every fight at full health and to never run short of healing between battles.