I brought my bike to a local shop to have a set or rear sets installed. After they installed the rearsets, he mentioned that my chain was at the end of it's life. I have only put 2,500 miles, but I'll admit that ive never lubed the chain. Would a chain need to be changed this quickly? I have never raced the bike, most of the miles were from commuting. Also, he mentioned that my brake fluids need to be changed, as they are dark. Is this shop BS?