#5 Back Then.
Centuries ago, when watches were introduced to humans, it was popular as pocket watch and was meant to be kept in the left pocket.

#4 Looks Matter.
Even though the watches were to be kept in the pocket, yet it was made stylish and elegant. And it was the only fashion people followed to keep a watch.
There's more to reason, go down to know more.

#3 The Story Behind.
One fine day, something stroke on someone's back of the brain and he decided not to follow the trend and began to wear the watch on this hand.
But the story doesn't end here. There's more to reason, go down to know more.

#2 Simplest Way Out.
Wearing a watch on the left hand is way more convenient for the right handers as they can check the time while working over. Also, monitoring and handling becomes easier.

#1 Extended Life.
There's one more benefit of putting it on the left hand. As the left hand is utilized occasionally, the chances of getting scratches and other damage are competitively less thus letting your time instructor to have a longer life.