I've never used one. However, years ago I learned that I could over-torque bolts enough to strip the threads in cheap aluminum parts. Since then, I have made sure to use only high-end, strongly made parts and I have not had any issues.

My confession is true. I am sure that since that time I have gotten much better at gauging torque when I tighten a bolt, but I still don't use a torque wrench. All that said, I wish I had gotten a small torque wrench ages ago, so that I would not have had to learn all this by trial and error (which means destroying components.)