The "spare key" one if problematic. I've looked at, and even used, various solutions for keeping keys together in some form other than a jangly mess, but there's always that one problem key: the car key with big fat end due to an RFID chip. And of course, there's also usually a fob for the locks/alarm. Car makers just seem to assume you really, REALLY want to carry two big lumpy plastic-and-metal objects in your pocket. Until they change their thinking, car keys will never be amenable to compact storage/carry solutions.