Necessary, no. Convenient, yes. I have a lanyard and different "holders" that I use depending upon where I am. Onboard I just have a slim card holder for a key card. When I go ashore I have a small zippered wallet type holder which can carry my key card, passport card, credit card, cash, & change. I wear them inside my shirt so no one can see them (yes, they look geeky, but we are senior citizens who ARE geeky). My husband has a men's equivalent so that we're not dependent upon pockets to hold everything.