I was taught in school that when you have a list of items, you do not use a comma before "and." For ex: "She ate apples, pears, peaches and grapes." The reasoning behind this was that in a list, the comma replaces "and" - the comma is used so that you do not have to say "She ate apples and pears and peaches and grapes." Therefore, when you use "and" you do not need to use a comma. Some of my teachers said it was optional to put a comma before "and" and some said absolutely not to do it. NONE of my teachers said we SHOULD use it. Now I notice that the rule seems to have changed. All my kids tell me they have been taught to use the comma and several reputable websites say to use it. Different reputable websites say not to use it, however. Because it was drilled into me I HATE seeing it used this way. Which way is correct?