All in all I have two bags I frequently use. A backpack if there are some more items to carry and a shoulder bag which I only use short walks and if I do not ant to carry a backpack with me for any reason. But that actually means I need to pack various items I tend to have always with me from one bag to the other, which includes a pen, notebook and calendar, some painkiller and a small switchblade which comes in handy as an all-purpose tool quite frequently.
So I bought a new knife to have one in every bag. I decided for an arty looking one which could not really mistaken as a weapon.