Up to this point, if you had a watch and you wanted it to do something useful instead of being a glorified, leather-strapped wristlet, you had to wind it twice a day. Forget, and the gears would eventually slow to a stop, and you'd be late for work. "I forgot to wind my watch" was the "I forgot to plug in my phone" of its day. But in 1957, the Hamilton Watch Company introduced the electric watch to the world, the Hamilton 500. It was $89.50, or about $745 in 2014. It had a tiny, battery-powered tuning fork inside, and the vibrations of the tuning fork replaced the need for winding. The problem was, as always, the battery. Hamilton worked for years to get it right, but production of the electric watch ended in 1969.