Is it permissible to wear a watch during prayer?

If the intent behind wearing a watch is to place it on the hand during prayer, then that is makrooh (disliked) because it contradicts khushu' (devotional humility), but it does not invalidate the prayer if the action is minor. The standard for determining whether an action is minor or excessive is common practice. However, if the intent is to pray while the watch is on the hand, then that is permissible.