Just one example: when I’m working on a random unknown bolt, I have to try two sets of sockets on it because I don’t know if it’s metric or imperial. Worse, the

Just one example: when I’m working on a random unknown bolt, I have to try two sets of sockets on it because I don’t know if it’s metric or imperial. Worse, there are some sizes which are close enough to grip and seem like a fit, but which will damage the head when more than moderate torque is applied. There are lots of little things like this, multiplied by millions of people.