Buffer
The buffer is a mechanic in Super Smash Bros. Brawl and Super Smash Bros. 4, which allows players to successfully input actions up to 10 frames before they can actually be executed. Whenever a move is used in Brawl, a window of 10 frames is created at the end of every move and animation, in comparison to Melee's 0 frames. During this time, any input will be carried out the first frame possible as soon at the move or animation is finished. This is beneficial, as it allows the player to perform a move the instant another move or animation is finished, allowing them to respond as soon as possible with greater input accuracy; a feat which would otherwise require frame precision. Buffering is required in many damage-racking combos to minimize the opportunity for the opponent to escape.
However, there are also negative effects to buffering a move. Buffering may lead to unintentional inputs that carry out (e.g. attempting to buffer a jab nearby the ledge while shielding, which would result in using a neutral aerial off the stage). This kind of situation can be deadly to characters with laggy neutral aerials, such as Ike, whose recoveries do not provide enough vertical distance to recover after the attack ends. Project M has an option to turn off buffering.