A wearable component of an implantable medical device adapted to work with a sensor that detects the strength of the magnetic field emanating from a magnet situated in the implanted portion of the device. The wearable component can be fitted with a magnet that can be programmed or adjusted to the required strength. The system can automatically determine the required magnet strength, and also program the magnet to have the required value. The technology removes the conventional means or the need of audiologist/clinician to perform manual determination of the magnet strength by trial-and-error, and streamlines the process of magnet determination. The tedious and error-prone manual process can now be an automated additional step in the process of fitting an auditory prosthesis. The system removes the need for manual intervention and guess-work by the clinician fitting the wearable component. The system helps to standardize fitting practice across clinics.