Accutron Changed Everything:
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Prior to 1960 no wrist or pocket watch, regardless of price, had ever achieved the standard accuracy of an Accutron. Three centuries before Accutron, the "balance  wheel" and "escapement" method of timekeeping was invented, and it remained the basic technology of mechanical movements until November 24, 1960. On that momentous day, an inherently accurate timepiece with only 12 moving parts went on the market and rendered escapements and balance wheels unnecessary. In fact, Accutron is the grandfather of all modern quartz watches.By the beginning of 1961, a timepiece that separated every second into 360 equal parts could be found in stores all across the USA and around the world soon after.
The new technology was inherently accurate and even more incredible is the fact that the very finest of today's mechanical chronometers can have hundreds of moving parts and yet, the ticking of their balance wheels still can't exceed 8 beats per second.

Also see: The Paradigm Shift