>>32496753All jumps in Traveller's main setting take one week in ship time, then you either do another jump (if you're on a ship with big fuel tanks) or you stop off somewhere to refuel. (And get dragged into Adventure!)
That one week of downtime for players will likely be spent on training to improve skills, if you're using Mongoose.
They might also want to gamble or interact with other passengers or crew.
In-jump hijacking attempts might even happen once in a blue moon -- criminals trying to seize a ship by surprise. Chances of success are pretty poor unless they know something about the ship's computer that will let them override security, and the crew are lax about weapons, but even so, desperate people will still try it sometimes.