Chapter 3-1: The Comma (,)
Comma usage is in some respects a question of personal writing style: some writers use commas liberally, while others prefer to use them sparingly. Most modern North American style guides now recommend using fewer commas rather than more, so when faced with the option of using a comma or not, you may find it wise to refrain.
For instance, the use of a comma before the "and" in a series is usually optional, and many writers choose to eliminate it, provided there is no danger of misreading:
We bought scarves, mittens and sweaters before leaving for Iceland. (comma unnecessary before "and")
We ate apples, plums, and strawberry and kiwi compote. (comma needed before "and" for clarity)