I'm definitely not a pro mechanic but ride 15k miles/year and keep my local shop's wrenches plenty busy :-)
That said, lots of basic maintenance and repairs can easily be done at home, though some require special tools. A lot of bolts should be tightened to very specific torque for safety and performance. This is especially common where carbon components are involved to avoid cracking. So us home mechanics either have to use basic tools and go with gut/feel, or upgrade to torque wrenches. That's usually expensive.
These products (multiple preset torques offered) are a great option--the fixed torque is less flexible that professional tools, but is therefore simpler to use and these are offered in the most commonly needed torques. I don't need them very often, but at this price it's nice that I can have them in the tool box and save an occasional trip to the shop.
I've been using the 5Nm for about 1.5 years. It's a great tool and the little case helpful.
