You got lucky, or you've treated your tools well. And you're right and wrong about the sensitivity of these tools. The lower cost ones can be very delicate in terms of holding calibration. But toughness is one of the distinctions of a professional grade tool. That said, it's usually a lot easier for a home user to be careful with his torque wrench that to cough up the price of a Snap-On.
This is just a quick reply to the whole harbor freight torque wrench thing. I have one of the same wrenches and after a fulls years use, I took it to work and had it calibrated and it was dead on. Its true that a "good" torque wrench can cost a pretty penny, but even one of the most exspensive wrenches is not good if it is not calibrated annually, and it doesnt take much to throw them out, simply knocking it off your work bench and it landing on the garage floor can send it out of cal. Just my 2 cents.
One really good thing to remember to do is to back the torque setting collar on a clicker off to just below the lowest setting when you're done with it. Springs are something the Chinese don't do well, and leaving a wrench run up to 30-40% or more of its capacity will set the spring after a time. Much faster on a cheap one, too.