...... How do I decide if I need an indoor or outdoor table? 

Indoor tables are not weather resistant but provide an excellent bounce and are good value for money. However they must not be stored in damp conditions (such as a barn or garage) as exposure to moisture will cause the playing surface to crack. They will also warp if left outside in the sun for only a short period of time. Outdoor tables are more shock resistant and can be safely stored outside all year making them more long lasting.