Life skills were introduced in The Sims 2: FreeTime. They are skills that a Sim can learn to unlock special interactions or abilities. Unlike other skills, they are not learned incrementally. A Sim will not have a life skill until he or she has learned it completely.
This skill can be learned by reading a book from any bookcase. Once learned, it allows a Sim to "check" on babies. A thought bubble will appear indicating any motives needing attention. The symbols for hunger, bladder, and so forth are the same as they are when older Sims need something and began waving at the player.
Sims with this skill build body skill faster, gain fitness faster and lose it slower, and lose energy more slowly. This skill was bugged in the initial release of Apartment Life, so that Sims who learnt it would learn body skill instantly. The bug was fixed in the Apartment Life patch, but then broken again in Mansion and Garden Stuff. Several mods fix this bug, such as M&G Physiology Fix from Mod The Sims and alfixes mod from More Awesome Than You. These two mods conflict, so use either one of them.
Allows a new interaction: "Repair relationship with...". When this interaction is used, the Sim using it will start trying to fix the relationship between the two Sims who have a romantic relationship problem. If a couple is divorced, their relationship cannot be repaired. If the repairing Sim was part of a cheated relationship, the relationship cannot be repaired directly by them.