I recently noticed my rear tire was wobbling side to side. I took my bike to the LBS and the guy yelled at me saying that I don't take care of my bike? The rear axel is cracked & needs to be replaced. My bike is 8 years old and my question is did I go down a big curb too hard or does the part slowly break down over the years. I decided to take my bike to another LBS to have fixed.

Thanks