A method involving a portable or wearable medical device the medical device having an operations sensor, a processing unit and a memory and a cell phone transceiver integrated in a housing and is able to store information in the memory about time points for operation events, the medical device being carried by a user, and a client device carried by the same user, where the client device comprises instructions that causes the client device to determine the position at least at predetermined time intervals or where the cell network provides the position of the client device to a server at predetermined time interval, the method comprising the steps of: a) the client device determining the geographical position for the client device for at least a first time point and a second time point, and transferring these positions and time points to the server via a data connection, or the client device having its position determined for at least a first time point and a second time point by a cell network, and the cell network providing the positions and time points to the server, b) the medical device determining, using the operations sensor, a time point for when the medical device has been in use (third time point), c) the medical device, using its cellular radio transceiver, establishing a data connection to the server and transferring the third time point to the server, d) the server selecting, among at least the first time point and the second-time point, the time point that is closest to the third time point, e) the server using the position and the time point selected in step d) to retrieve position-specific data selected from the group consisting of a weather or climate parameter, air pressure, humidity, temperature, traffic, air pollution, air particle density, air pollen density, person density and altitude above sea level, for the position and the time point, then f) the server using the position-specific data from step e) to determine whether the medical device should be serviced or replaced. a) the client device determining the geographical position for the client device for at least a first time point and a second time point, and transferring these positions and time points to the server via a data connection, or the client device having its position determined for at least a first time point and a second time point by a cell network, and the cell network providing the positions and time points to the server, b) the medical device determining, using the operations sensor, a time point for when the medical device has been in use (third time point), c) the medical device, using its cellular radio transceiver, establishing a data connection to the server and transferring the third time point to the server, d) the server selecting, among at least the first time point and the second-time point, the time point that is closest to the third time point, e) the server using the position and the time point selected in step d) to retrieve position-specific data selected from the group consisting of a weather or climate parameter, air pressure, humidity, temperature, traffic, air pollution, air particle density, air pollen density, person density and altitude above sea level, for the position and the time point, then f) the server using the position-specific data from step e) to determine whether the medical device should be serviced or replaced.