An apparatus including a sensor carried by a racquet and an indicator in communication with the sensor. The sensor outputs a notification based on (a) the number of hits by the racquet based on signals from the sensor and (b) at least one of an elapsed time since a last stringing of the racquet and an input skill level of a person using the racquet. Additionally, an apparatus including a racquet, a sensor carried by the racquet, and an indicator in communication with the sensor. The sensor can be a strain gauge, a load cell, an acoustic sensor and a vibro-acoustic sensor. The sensor outputs a notification based on the number of hits by the racquet based on signals from the sensor.
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