Changes to the vibrational frequencies of a drill string or BHA are monitored for prognostic health monitoring purposes. When one or more orders of resonance frequencies deviate from a baseline frequency, the magnitude of the deviation, and possibly the rate of deviation, is evaluated. When the deviation exceeds a threshold value, an alert is triggered. The alert may be triggered by downhole processing of the vibration data and conveyed to an operator to allow changes in operational parameters or removal of the component from the wellbore. The alert may instead be triggered by post-run processing of stored and dumped data, that can be used to evaluate whether the tool can be re-run, or whether it should be inspected, repaired, or scrapped.