Thanks to everyone who posted answers to this question it was very helpful!
It is not necessary to use a back up method for the first 3 months. Of course you *can*; but why stop at 3 months?
Point being is that after 7 days, you are as protected as you are after a month, 2 months, 3 months, a year.
It is not necessary to use Plan B or the morning after pill in the situation the original poster described.
No birth control is fool proof, but it is not necessary to use any other method while you are taking birth control pills correctly, unless you need to be protected against STDs. In that case you would always use condoms for added protection.
What you say is true, they do say after seven days it is "safe" but nothing is fool proof, I would still suggest using back up for the first month-three months just to be sure, and this is only if you don't miss pills, you should read the instructions that came with your pills on how to handle back up if you miss pills...
It isn't necessary unless you missed pills. You are protected.