I think (rather, I know) I need to calibrate my monitor and was looking at the spyder 2 or 3. Please forgive my ignorance, but is this a "one time" use item? As in, plug it in, calibrate, and then you have no more use for it? I'm looking at the price and it's kinda hard to swallow if that's the case. Can you buy them used or even rent?
Thanks!

