At this point there's no evidence that any repaired/replacement N900s are any better than the original.

So obviously if you have a failed device you want a replacement, but looks as if there's a real design issue here a manufacturing EC is needed to correct the issue permanently -- at least for any devices returned broken

With a device such as this I think it's reasonable to expect a minimum of 2 usb insert/remove cycles per day over say a 3-5 year period

The broken devices may well be irrepairable, but that's down to a potentially serious design flaw and has no bearing on whether the device has to be replaced.

For now I'm happy but will be very careful with USB. I'm sure NOkia will come good in the end, and meantime I have the protection of consumer law, shared with my credit card company (since I purchased sim free), as well as mobile insurance (which I shouldn't need to use). ANd if a design flaw is shown that protection lasts well beyond any 2 year warranty period