Beat Count

Modern watches usually have "Beat" or "Train" count of 21,600, 28,800, or 36,000 beats per hour (bph). Older watches, particularly pocket watches, are typically outfitted with 14,400, 16,200, and 18,000 bph.

Hairspring, Jaeger-LeCoultre - Calibre 849

Accuracy is generally better on movements with higher bph. It is a simple way in judging the quality of a movement. The higher counts in beats, the smoother run of the second arm will be. Hence, higher end watches always employ movements with higher beat counts.