Are you asking about the actual Exam?
Then, Time will be ticking on the screen. You need not carry a Digital watch.

Well, I havent taken the GMAT yet, but I have seen GMAT PREP. I believe, it would be the same.

The software is the same as it is on GMAT prep. You aren't allowed to bring a watch in to the room with you.

I don't know if others do the same, but instead of paying close attention to the time, I plan to check it every 5 to 10 questions to monitor my pace. So when I'm on question 10, if my time remaining is more than 55 minutes I'll slow down and if it is less I will speed up.

One way to ensure you don't get hung up on a single questions is to practice with a timer. If you consistently time yourself to the appropriate length (e.g. 2 minutes for a math problem), you will instinctively recognize when two minutes is up. Think about using your microwave. If you set it to 60 seconds often enough, at 59 seconds you automatically start listening for the bell.
Of course, you don't just automatically stop when you reach two minutes. You take a second to assess your progress and determine whether you can finish quickly or need to move on. The answer will depend to some extent on how well you are progreessing overall. If you are ahead of schedule it may be worth while to spend a little extra time.