First of course is finding a dentist you trust, like other posters have said. Once you have a good relationship with a dentist and feel like their recommendations are solid, I would just go with what they suggest. I had a really terrible experience with a wisdom tooth that my dentist (who I now really trust) suggested I get removed, but I decided to wait longer. My tooth broke through the gum surface, but just barely so I didn't even realize it was happening until it got infected, and suddenly was causing excruciating pain. Because of the way that it broke through, the removal was pretty terrible, and I was in severe pain afterwards for 3-4 weeks. Next time I get x-rays, if he suggests its time for any of the others, you can bet I'll be in his office asap to prevent a repeat of my previous experience.