Similar to checking if the door's locked, I also check before I leave and often mid journey to see if I have the Key Three items in my pockets. Wallet-Phone-Keys is the mantra, repeated whilst tapping the items in my pockets, although I generally tap my phone and wallet whilst calling them the other. Phone and wallet go in my left pocket, keys in my right pocket. I don't like to not be able to feel my keys, part of the reason my full bunch of keys is fairly sizeable.