People all over the world wear watches on their wrists. Generally it is observed that men wear them on their left hand while women wear them on their right hand. Now the question is why do men prefer left hand and women prefer right hand for wearing watches?
No watch is particularly meant for wearing in the right or the left hand. Its just a simple wrist watch. Wearing a watch on our left hand has a practical reason; we do most of the work like grabbing, holding, writing etc with our right hand, the dominant hand. So wearing watch on the non-dominant hand (i.e. left hand) has became a custom as it would be easier to check out the time on the hand we use less and where it does not get stuck or dirty or even damaged.
It is just easier for a right handed person to strap up the watch on their left hand if the buckles are too tricky to tie on. Another aspect of following this custom is that we generally perform all our religious rituals with right hand as it is considered that all good things should be done using right hand. Tying it on left hand makes the person hassle free while offering pooja or performing any religious service with right hand.