I keep having a problem with my derailleur hanger. It keeps ending up being bent. I keep taking it to the bike shop and having them fix it. Now, it's bent worse than it has ever been, making adjustment of the derailleur impossible. Is there ever a time when it's just a lost cause? Do you have to buy a new frame in that case? I've never really contemplated this question before and can't find much online. Maybe someone here has had a similar experience?