The End game and Counting letters.

Too often I have been within a few points of my opponent. 0 letters left and 4 in my rack. A quick count of the board tells me that there are 94 letters played. So 94 + 4 maens that he has 6 on his rack and another look on the board tells me that only 4 Ss have been played. So he has an S and oh yes where is the Q?

Now I have to be cetrtian that I do not allow him to use one of the two Is that I have been stuck with (QI!).
So if I can use the I safely and perhaps place the last one to empty my rack I might win....

That is just an illustration of how a game can be won or lost and why counting is important.