I have 1 hour and 15 mins layover at DXB Dubai Airport will it be enough to buy a watch at Dubai Duty free? (I have same terminal [TERMINAL 3] to board in and out)
If your flights run to schedule then probably just about but it will be a bit tight. It is a well managed and efficient airport but very large, your arrival and departure gate may be far apart. I'd suggest that when you arrive, carefully check your gate for the next flight and ensure that you allow enough time to get there.
Also, I would not assume that the prices are good. Research the items that you are considering and prices available elsewhere e.g. online.