What is it that they need to relax from? Eileen, prior to her defection, liked nothing better, after a hard day beating dragons, than a stiff drink, a long relaxing bath and plenty of sleep. Jenny, after a hard day arguing with her mother (and it is difficult to win arguments with Eileen), prefers a long relaxing bath and a read of a good book (and in her case often the Good Book too).
Do your characters have hobbies and if so, which, and how often can they get to enjoy these? What are considered normal hobbies by your fictional world and which abnormal? Can anyone access hobbies or are they restricted to those of a certain class?
Nobody can keep going all the time and the same applies to your characters. A glimpse of what they get up to when they unwind can be useful background material and can show you really do know your characters' likes and dislikes.