A wearable device comprising: a reusable component and a disposable component, the disposable component comprising a patient engagement substrate comprising adhesive on a bottom side, an electrode (255, 257) on the bottom side, a disposable component electrical connector (110, 253, 262, 316, 330), and a disposable component mechanical connector, wherein the reusable component comprises: a plurality of sealed housings mechanically coupled to each other and movable with respect to each other and a flexible circuit configured to provide electrical communication among electrical components within the housings, each of the plurality of housings containing one or more of a capacitor and a controller, a reusable component mechanical connector adapted to removably connect to the disposable component mechanical connector to provide a load-bearing mechanical attachment between a bottom side of the reusable component and a top side of the disposable component such that the disposable component is able to mechanically support and removably retain the weight of the reusable component on a patient at least partially through the mechanical connector, and a reusable component electrical connector (1, 253, 262, 312, 338) adapted to removably connect to the disposable component electrical connector (110, 253, 262, 316, 330), characterized in that: the disposable component electrical connector (110, 253, 262, 316, 330) is separate from the disposable component mechanical connector, the reusable component electrical connector (1, 253, 262, 312, 338) is separate from the reusable component mechanical connector, and the disposable component mechanical connector and the reusable component mechanical connector are configured to allow the reusable component and the disposable component to move relative to one another while still maintaining a mechanical connection. a reusable component and a disposable component, the disposable component comprising a patient engagement substrate comprising adhesive on a bottom side, an electrode (255, 257) on the bottom side, a disposable component electrical connector (110, 253, 262, 316, 330), and a disposable component mechanical connector, wherein the reusable component comprises: a plurality of sealed housings mechanically coupled to each other and movable with respect to each other and a flexible circuit configured to provide electrical communication among electrical components within the housings, each of the plurality of housings containing one or more of a capacitor and a controller, a reusable component mechanical connector adapted to removably connect to the disposable component mechanical connector to provide a load-bearing mechanical attachment between a bottom side of the reusable component and a top side of the disposable component such that the disposable component is able to mechanically support and removably retain the weight of the reusable component on a patient at least partially through the mechanical connector, and a reusable component electrical connector (1, 253, 262, 312, 338) adapted to removably connect to the disposable component electrical connector (110, 253, 262, 316, 330), characterized in that: the disposable component electrical connector (110, 253, 262, 316, 330) is separate from the disposable component mechanical connector, the reusable component electrical connector (1, 253, 262, 312, 338) is separate from the reusable component mechanical connector, and the disposable component mechanical connector and the reusable component mechanical connector are configured to allow the reusable component and the disposable component to move relative to one another while still maintaining a mechanical connection. a plurality of sealed housings mechanically coupled to each other and movable with respect to each other and a flexible circuit configured to provide electrical communication among electrical components within the housings, each of the plurality of housings containing one or more of a capacitor and a controller, a reusable component mechanical connector adapted to removably connect to the disposable component mechanical connector to provide a load-bearing mechanical attachment between a bottom side of the reusable component and a top side of the disposable component such that the disposable component is able to mechanically support and removably retain the weight of the reusable component on a patient at least partially through the mechanical connector, and a reusable component electrical connector (1, 253, 262, 312, 338) adapted to removably connect to the disposable component electrical connector (110, 253, 262, 316, 330), characterized in that: the disposable component electrical connector (110, 253, 262, 316, 330) is separate from the disposable component mechanical connector, the reusable component electrical connector (1, 253, 262, 312, 338) is separate from the reusable component mechanical connector, and the disposable component mechanical connector and the reusable component mechanical connector are configured to allow the reusable component and the disposable component to move relative to one another while still maintaining a mechanical connection. the disposable component electrical connector (110, 253, 262, 316, 330) is separate from the disposable component mechanical connector, the reusable component electrical connector (1, 253, 262, 312, 338) is separate from the reusable component mechanical connector, and the disposable component mechanical connector and the reusable component mechanical connector are configured to allow the reusable component and the disposable component to move relative to one another while still maintaining a mechanical connection.