Chiropractics are borderline medical fraud. Sure, your back/neck/whatever might feel better after they pop it....only to have it pop out again after sitting down in your carseat on the way home. This is because your tendons/ligaments get stretched and weakened from all the popping they do so they won't be able to hold the form unless you basically don't move for a few days. So people keep going to them again and again and again. Basically it's up to the patient to say when they've had enough, but few have enough faith in their own better judgement.