American Idol
The most popular contestants are usually not revealed in the results show. Instead, typically the three contestants (two in later rounds) who received the lowest number of votes are called to the center of the stage. One of these three is usually sent to safety; however the two remaining are not necessarily the bottom two. The contestant with the fewest votes is then revealed and eliminated from the competition. A montage of the eliminated contestant's time on the show is played and they give their final performance. However, in season six, during the series' first ever Idol Gives Back episode, no contestant was eliminated, but on the following week, two were sent home. Moreover, starting in season eight, the judges may overturn viewers' decision with a "Judges' Save" if they unanimously agree to. "The save" can only be used once, and only up through the top five. In the eighth, ninth, tenth, and fourteenth seasons, a double elimination then took place in the week following the activation of the save, but in the eleventh and thirteenth seasons, a regular single elimination took place. The save was not activated in the twelfth season and consequently, a non-elimination took place in the week after its expiration with the votes then carrying over into the following week.

Q: How many time can the judges save be used each season?
once