This buff causes one or more targets to regenerate HP at the start of their turn. The amount of HP varies based on the source of the Renew effect, whether or not each target has a companion with the +10% healing received reserve bonus, and whether or not each target is afflicted by Curse at some point during Renew's duration. Renew lasts for three turns in battle, including the turn it is first applied, unless the target is defeated or unless battle ends before three turns have passed. Renew lasts for fourteen steps out of battle, unless the party gets into a battle at which point Renew is cancelled.
Some companions and any Conjurer can learn a skill that will extend the in-battle duration of any spell that applies the Renew effect by an additional turn, with the same possibilities for an early end as listed above. The Conjurer version of the skill, Lasting Recovery, is learned in chunks of 25% along with the RenewMost spell and maxes out with a 100% chance of an additional round. The companion version of this skill, Lasting Renew, is a 100% chance of an additional round from the moment that it is learned.