Something ‘hurts’ then you have more significant issues. One, it’s going to be a lot more expensive to fix, two, if it hurts you’ve done more harm to the tooth than if it was taken care of preventatively. Old fillings break down, the tooth around large fillings breaks down. If you have fractures starting on a tooth it’s only a matter of time before those fractures can turn into root canals or implants. That’s when you start talking about large expenses. Some Dentists are willing to ‘watch’ things longer than others. It’s just a gambling game. It really just comes down to how proactive you want to be.