vacation setting



The "vacation" setting isn't just for vacation and can be used if you have emergencies, just need some time away from the site (of even just away from Daily chess games), get bogged down in your life/work and can't get on to make moves, etc.
Daily games can last months and tourneys can last years. While some people may plan out all their time off that far in advance, I imagine most do not and that doesn't take into account other unexpected things that can come up.
The amount available is for all vacation time taken, not necessarily in one event. So, a week here, a few days there and that can add up to your total allowed. Also, members only start with 7 days and build up from there.

Chess.com has a really cool cheat in vacation settings! Wait until the last minute of your time, go on "vacation", return and BAM an extra 24 hours! I had an opponent do that to me for a week in a dead lost position. Thanks Chess.com!
The don't really get extra time. When vacation is set, the system automatically removes 24 hours of time from the member's available vacation bank. If they come off vacation before the 24 hours has elapsed, the difference is added to games they are on the move in, up to the time control, except for no-vacation games.
The net effect is no different than if they took 24 hours of vacation, is done by design, and is not cheating.