I usually go out once or twice a day just because I can't stand being in the house for 24 hours.
A walk to the park does a world of good, and scientific studies show that being out in the sun can keep a person healthier AND happier. I can honestly say, one way to get me out a depressive state is just by walking outside to the bus, going to Target, then instead of cooping myself up inside the target waiting for the bus, I sit outside and just love it.