Renewal (回復, Kaifuku lit. Recovery); first introduced by the name Life (ライブ, Raibu) in the Jugdral Series, Guérison in the French version of Fire Emblem Awakening, Guarigione in the Italian one) is a recurring skill in the Fire Emblem series.
Renewal is a passive skill, meaning that it will always take effect without the user having to activate it in any way. Renewal takes effect at the beginning of the turn of the character who has it equipped.
The Renewal skill allows the user to recover 10% of his/her maximum HP at the start of the preceding ally turn (30% from Awakening onwards). For instance, if the character equipped with the skill has a maximum HP of 60, they will recover up to 6 HP at the beginning of each of their turns if he/she has been injured in any way.
The Renewal skill is generally less effective early on in a given game, as characters will have lower maximum HP early on. This does not often matter, however, as the skill is often made available late into the game.