Sounds bunk. I see the dentist about as often as you, and have never had to go in for multiple cleanings (though sometimes I can get some nasty stain along the molars, so I'm sure the hygenist loves me.
Though my most recent visit (a few years ago) had them using some tool that shot water, and vibrated exceptionally fast and it cleaned stain off relatively easily.
Though I think I'm a bit of an enigma. I have never really had strong brushing habits, nor do I visit the dentist regularly. Yet, I have never had a cavity. Go figure.
As for those talking about wisdom teeth, I had all four of mine pulled. My two top ones were coming in fine, but my bottom two were fully impacted, and were literally coming in horizontal, and would have eventually been pushing against the roots of my back molars.
I opted to be put under, because to remove the teeth, they had to cut my gums, chisel into my jawbone, and then proceed to break the tooth and pull it out, a chunk at a time.
To make things even more fun, the blood clot in my lower right socket came out, leaving the nerve fully exposed, and giving me the infamous "dry socket." The pain was nigh unbearable. The only thing that felt worse was when the dentist put in a strip to help cover the nerve. The pain was so unbearable that I actually passed out. I would seriously rather get kicked in the testicles. The almost as great part was that a week later, I had to have the strip replaced. Fortunately, the socket had started to heal so it wasn't quite as ungodly painful. Just exceptionally agonizing. About on par with a kick in the groin.
It was certainly the happiest time in my life