If a judge pauses a match for more than one minute while the round clock is running, he or she should extend the match time appropriately.
Players are entitled to use the full time of a round to play their match of Magic. Should some interruption come, time extensions are used to allow players a chance to fully play out their games. Players with a time extension who are still in a game when time is called should call a judge to ensure time continues to be kept accurately.
If the match was interrupted to perform a deck check, players are awarded time equal to the time the deck check took plus three minutes.
Because a deck check typically orders the deck in an intentionally non-random way, players should be afforded adequate time to randomize their decks before proceeding with the next game. While no longer codified, the benchmark for pre-game and between-game procedures is three minutes, so this much time is afforded to each player.
Feature matches at a tournament with online coverage receive a time extension equal to three minutes plus time elapsed in the round when players reach their table. This is not necessary if feature matches are being timed separately.
Players who are on coverage are doing so at the request of the organizer. We do not want to put players at a disadvantage because they simply have an interesting match to watch, and are doing the TO a favor. Of course, if the feature matches are timed separately we do not have to worry about the players being at a time disadvantage!
Certain slow play penalties add turns rather than a time extension. These additional turns are added to the end-of-match additional turns.
For more information, see IPG 3.3: Slow Play. If a player receives a warning for slow play, each player is awarded an additional turn, totaling seven additional turns if one player is warned and nine additional turns if both players are warned. Note that no additional turns are awarded if slow play is penalized during the additional turns procedure. This is chosen as a way to give back some of the time that was lost, without having to try and quantify how much time was lost.