The technology provides for a pair of earbuds. For instance, a first earbud and a second earbud may each include one or more sensors. The pair of earbuds may further include one or more processors configured to receive one or more first sensor signals from a first sensor in the first earbud and one or more second sensor signals from a second sensor in the second earbud. The one or more processors may compare the first sensor signals with the second sensor signals. Based on the comparison, the one or more processors may detect whether the first earbud and the second earbud are being worn by different users. Based on detecting that the first earbud and the second earbud are being worn by different users, the one or more processors may control the first earbud and the second earbud to use a shared mode.