While observing a speaker's behavior as he was delivering his speech, I couldn't help but be distracted from his message.
His content was impeccable and his delivery was good.
However, he had an annoying habit which got to me after a while.
As he was speaking, he was constantly moving from left to right, for no apparent reason.
Think of it as a pendulum.
If you are constantly moving the pendulum from left to right, it eventually hypnotizes you and induces sleep.
I'm not sure that would be an acceptable outcome for your speech! Don't get me wrong: moving is perfectly natural and normal and encouraged when you speak.
However, pacing is not.
Pacing involves a repetitive movement which can become numbing or distracting.
Our body is not meant to stay in place, unless it is time to sleep...
and for some people, that doesn't change anything! Therefore, we have a need to be in motion.
This need to move can be compounded and accentuated by a bit of stress or nervousness caused by speaking to an audience.
To compensate, we move around.
On one hand, moving on stage can actually help to get your point across because it requires your audience to change its focus periodically.
But on the other hand, standing still helps them to concentrate because they don't need to pay attention to a moving object.
So you need to balance those two requirements.
A few guidelines that can help you if you tend to pace as you speak:

• Stand still while making an important point: when you are saying something that holds more importance than what you previously said, stand still to let the information sink in for the audience.
  
• Move when making a transition: a transition is when you go from one point to another.
  Those are good times to move from one spot to another, especially if you are using the anchoring concept.
  
• Move when acting: public speaking is a performance and sometimes you need to act out some of your words.
  Don't just say it in words, let your body do some of the speaking also.
  
• Move to connect with the audience: this is one of my favorites.
  I like to move into the audience, in the aisles between the seats in order to get closer to them.
  When I do, I just keep delivering my speech, as if it was no different than being at the front of the room.
  It is a powerful way to connect with the audience.
  

I would never recommend that you stand still during an entire speech.
That would make it boring for you and boring for an audience.
So unless you have a situation that prevents you from moving, don't hesitate to do so.
I caution you not to overdo it.
In Quebec we say "Trop c'est comme pas assez" which roughly translates to "Too much is no better than not enough.
" It is important to learn to balance certain elements of public speaking, to ensure that you do not overdo it one way or another.
How do you know what is too much and what is not enough? Practice, practice, practice.
The more you do it, the better you will be able to gauge it and adapt yourself.