Tools are judged by their ability to do the job repeatedly and without fail.
That's not how anything is judged -- they are judged by expected TCO. And that TCO includes initial cost, minus expected performance but plus the expected value of failures multiplied by the cost of each failure. All of these vary by the job that the tool is being asked to do.
To give an example, if the wrench is going onto a deep-sea oil platform where replacement will be very costly and will cause very expensive delays, the last factor is very high and so reliability will be at a premium.
On the other hand, the local auto mechanic probably has a dozen wrenches and a parts truck that comes around every other day that can bring a new one in for nearly zero overhead. So she might be willing to accept a higher failure rate.
On yet another (third?) hand, someone working in aerospace or other sensitive area will likely need a wrench that can accurately deliver a set amount of torque. In this case, the accuracy of the tool will be the most important concern, since failure of the product (satellite, jet engine, space shuttle booster rocket clamp attachment) will be far more costly than failure of the tool.
So there you have it, three examples of how making general statements about how we judge things is complete bollocks. The "right tool for the right job" might be clichÃ© but the lesson is less about picking the right tool and more about thinking about the properties that are priorities for the job.