Dentistry seems pretty subjective. Why is that?
There are many procedures that can be done to teeth with issues that could alleviate the problem. For example, if someone breaks half of their tooth, a really big filling might work. Also, a crown might fix the problem, or someone might determine that a root canal is necessary THEN a crown. Another dentist might say the best thing to do would be get the tooth extracted and get an implant. All of those are viable options with varying costs and time commitments. Depending on the situation, some treatment will be more or less aggressive/conservative with different degrees of longevity.