I’m building a watch,
My first attempt had an accuracy of 1 second out of 80 seconds. At first glance i thought well that is ok, that is 98.75% accurate. but if you think about it, that is a whopping 1080 seconds (18 minutes) a day of lost time.
With my next attempt I lost 9 second over 27180 second. This was much better at as accuracy of 99.96689% but over a year this is still 10442 seconds a year (174 mintues or 2.9 hours).
So on my third attempt I have successfully tweaked it to 1 second every 172800 seconds or 99.9994% accuracy or 3 minutes a year. I am happy with this.
Work will continue, as i now start on a stop watch and alarm feature.