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), channel energy uses, and other abilities 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 wish to spend an hour or so fleshcrafting yourself or your corpse puppet. By default, it's assumed that you've granted at least one of each fleshcrafting benefit to yourself each day after rest (see typical tactial opening for details).