[After the 24 hours are over, the watch will disappear, and so will the appearance shifting ability disappear as well.]
Jaden looked at the series of prompts describing the function of the appearance shifting watch. He could not help but be excited. To be able to change his appearance, it implied that he could get out of a situation that was quite difficult for him to handle by himself, or escape from the person that he could not handle.
The only downside was that the appearance shifting watch could only be used for 24 hours, before it disappeared. In short, it was a consumable item.
From this, Jaden could immediately infer that he was required to only use the watch when necessary. Otherwise, it would be a waste for him to test out the abilities of the appearance shifting watch.