expand_less Generally, characters rest to recover their spells and daily abilities.
You can use downtime to rest and recover. It is assumed that you spend 8 hours resting at night, which allows you to recover 1 hp per level per day and 1 point of ability damage for each affected ability score. If you spend a full day of downtime resting in bed, you recover another 1 hp per level per day and another 1 point of ability damage for each affected ability score.
In your case, you also recover your magical energies (spell pool and channel energy), rage, and inspiration whenever you rest for 8 hours or more.  Though you do not need to prepare your spells ahead of time (by pre-allocating spell points to spells), you may still need an hour or so to practice your magical skills and martial maneuvers.