Placing a comma after a conditional statement

Question

I've always had difficulties in figuring out where commas should be placed. For example, in a phrase containing a conditional statement, how should I write...

• If they don't arrive by noon, she'll be worried.
• If they don't arrive by noon she'll be worried.

Answer 1

So far as I understand it: if you are putting the conditional statement first, you should put the comma at the end of it. You don't need a comma if the conditional statement comes afterwards.

Treat the condition as the independent clause and the result as the dependent as wikipedia describes. http://en.wikipedia.org/wiki/Comma#Separation_of_clauses

Answer 2

I'm not 100% clear on the rules, or if they even exist, but I often find that a comma does not hurt. The lack of commas in a complex sentence, though, often makes it very hard for me to grasp the meaning in the first read.

Eats shoots and leaves.

versus

Eats, shoots and leaves.

As found here.

Answer 3

I was once accused by a very particular English professor of sometimes having too many commas in my sentences. He asked what rule I was using to place them. For some, I said the commas are for pauses, for others, they simply follow the standard rules. He did give me an A for the class, which emboldened my continued use of them in that way.