Fighting Kottos (Monster Arena) Bribing Achelous fiends (Mt. Gagazet Cave waters) Steal from Behemoth Kings (Final Dungeon)
Of those options, the best way to farm Healing Springs is by defeating Kottos at the Monster Arena. It has 20 Healing Springs as its common drop (~87%). But if you’re having trouble reliably defeating Kottos, you can also get 16 Springs by bribing Achelous fiends with 167,000 gil. Or if you’re too weak and/or poor on Gil, you can always steal a single Healing Spring from Behemoth Kings. All that said, bribing or fighting Kottos might be the better choices. Kottos is unlocked at the Monster Arena after capturing one of every fiend on the Mi’hen Highroad. The list is as follows:
Mi’ihen Fang Ipiria Floating Eye White Element Raldo Vouivre Bomb Dual Horn
And finally, you can get a one-time gift of x99 Healing Springs by unlocking Sleep Sprout at the monster arena. Sleep Sprout is unlocked after capturing five copies of every fungus-type fiends in Spira. There only three fungus-type fiends, but you’ll need five of each one:
Funguar (Mushroom Rock Road) Thorn (Cavern of the Stolen Fayth) Exoray (Sin Interior)
What Are Healing Springs Used For?
These can be used in a variety of ways that all pertain to the spell Regen. When used with the ‘Use’ command, a Healing Spring casts Regen on a party member. You can also use Healing Springs to customize Auto-Regen and SOS Regen on armor, as well as teach an Aeon the Regen spell.
Auto-Regen requires x8 Healing Springs SOS Regen requires x12 Healing Springs Regen (Aeon) requires x60 Healing Springs
Furthermore, as is the case with all items in FFX, Rikku can mix up Healing Springs to create some pretty cool results. Here are a few of the coolest: Megalixir (Antidote + Healing Spring): Fully restores the party’s HP and MP. Ultra-Null-All (Healing Spring + Healing Spring): Applies Cheer, Focus, Aim, Reflex, NulBlaze, NulShock, NulTide and NulFrost to the party. Ultra-Cure (Speed Distiller + Healing Spring): Fully restores the party’s HP as well as curing all negative statuses.
Are Healing Springs Worth the Farm?
I don’t think so. Regen is a spell you can get reasonably easy, and is just as reasonably cheap to cast. Auto-Regen and SOS Regen sound nice, but you only have so many ability slots on your armor. And ultimately, Regen isn’t as useful as stuff like Auto-Protect and Auto-Haste. Teaching it to an Aeon could be useful, but that’s a very niche purpose that might not see a lot of use. You’re probably better off just unlocking Sleep Sprout to get the ninety-nine freebies, and then using them for Rikku’s mixes – because that should be way more than enough.