It depends on how long I am going out for, where I am going, and the weather (sunglasses, hat, etc.)
Short solo session:
Apt. building keys (optional when vaulting balcony)
Medium solo session:
Keys, Wallet, Phone, Water bottle
Long solo session:
-back pack-
Keys, Wallet, Phone, Water bottle, Med-kit, Box cutter, Deodorant, Purell, Food, Gloves, Extra clothes (T-shirt, socks, pants.), Mp3 player
Med/long solo Session + MA Class:
-back pack-
skateboard (optional), Keys, Wallet, Phone, Water bottle, Med-kit, Box cutter, Deodorant, Purell, Food, Gloves, Gi, extra shoes (optional), Training knife, Mp3 player
Med/long group session:
-back pack-
Keys, Wallet, Water bottle x2, Med-kit, Box cutter, Deodorant, Purell, Food, Gloves, Video camera
I also always wear a watch.