How do you analyze usability?

Here are a few methods I have devised for evaluating a piece of adaptive equipment. If it doesn’t fail these tests, it’s good!

The Breakage Test
Can you break the device within the first week of normal operation?
The Speed Test
Can the user complete standard tasks in a time-span comparable to any average user?
The Error Test
Can the user complete a variety of tasks repeatedly with no errors attributable to the adaptive hard-/software?
The Panic Test
Can the user complete a series of tasks with no extra time and no margin for errors? (Like, say, …last-minute HTML editing?)