What factors limit the accuracy, frequency response and stability of a frequency counter?

A frequency counter's operation relies entirely on counting incoming pulses over a specific timing window. This timing window is generated by an internal oscillator called the time base. Therefore, the overall accuracy and stability of the counter are strictly dictated by the accuracy and stability of this time base. Furthermore, the maximum frequency the counter can successfully measure (its frequency response) is limited by the switching speed of its internal digital logic circuits. If the input signal cycles faster than the logic can toggle, the counter will miss pulses. Distractors mentioning the 'number of digits in the readout' are incorrect because extra digits only provide higher display resolution, which does nothing to improve the underlying accuracy or stability of the actual measurement.