In matches, it is critical to adjust your in-between-point-speed based on several factors.  If you have lost several consecutive points, take your time before serving or receiving.  If you are feeling fatigued near the end of the match, take your time.  If you are unsure of the proper strategy to use next, take your time.  If you feel in control of the match and physically feel good, then it is a great strategy to play fast between points and finish the match asap.
 
In a recent easy match for me, I beat a 2000-rated player in 1 min 40 seconds.  Before he had time to properly consider what was happening, the 11-point game was over!  Last week, I played 1 game against a 2500 rated player and the game took about 8 minutes.  Between each point, I walked slowly to get the ball, took my time before serving, took my 6-point-towel-breaks, and considered carefully before choosing which serve to serve.  Each point was a battle and I needed to stop my opponent’s momentum.
 
So, as you can see in the above illustrations, you should try to play slightly faster when things are going your way and try to slow down the game when you are having problems.  It is actually illegal to slow the game too much, so don’t get excessive.