(sorry for my terrible english ) It seems that the characters in Star Trek use the Holodeck to rest, but sometimes it seems just the opposite. After a hard day's fighting the Kazon, your only desire is to go in a Holodeck to fight the enemies of Captain Photon?!?! Or after you re-create the Battle of the Ardennes, are you really ready to beam down on an unknown and dangerous planet? At least you would not be tired (and unfit)? I think the concept of shifts exists to allow the crew to rest to be ready for their duty. But what if they do in their spare time the same things when they are in active duty, changing only the background? Maybe the captain should ask his/her people not to exert themself in their spare time? What do you think? ps In theory, how many consecutive hours a crew member spend into holodeck..?