My friend and I have been traveling in the past and will be traveling soon again. For economy reasons we will be sharing accommodations. We usually go for AirBnB. The problem with renting a private room in a place (or usually also when having the entire place to ourselves) is that there's only one key to be had. Our sleep rhythms and daily routines are so different that it's becoming an obstacle.
Is there a smart way to cope with just one key between two people? It seems to be often that it cannot be left in a lockbox outside because you need it inside the house or on your way to the apartment.