Speaking for the 1900s at our facility:
About half are in really good, near new shape. The other half are danged tired (one of them this week decided that Ground Fine was an altogether superflous thing for an engine to do, so it was idle to reverse--nothing in between). But even those are pretty much ready to go to a freight operator somewhere.
Raytheon has been auditing the various 1900 storage facilities this week, because I guess they expect a rather good time to sell them soon. But like someone said: the ones with two engines get started, taxied, run up, most of the sytems checked, and then put back into storage--to be run in another month.
Some of these are at the end of thier useful life, but the vast majority are merely in a holding yard for the expected sale when the economy improves. We have heard of some of the smaller passenger airlines seriously looking at trading 402s and Navajos for the 1900s--because they're really not that much more expensive, and somebody seems desparate to get rid of them.
Dan