IPhone chargers keep breaking, why?

My iphone 4 charger stopped working after not even having it for a month and has not been chewed or damaged in any way. I bought another one and the NEXT DAY after opening it and using it, it stopped working. Third back up charger that came with the 2nd one, I started using a few days ago and have been super careful with it and hardly touching it and it is super stiff from being new and today this afternoon STOPPED WORKING… WHAT IN THE WORLD… I thought it could be my outlet but I have a powerstrip extension… What is the problem?(phone charges fine on my brother's charger which he has had for the same amount of time as my first one)

Are you sure it's the charger that is broken? I've had issues where I thought it was the charger but found out that it was the cord from the charger to the phone. Try your charger with your brothers wire on your phone and see if it works.