We say they are not usable.

I am not convinced my suggested methods are actually as usable as I think they are.

It corrupts data so it's not usable, but we have developed a cleaner to cope with this,

We don't except junk. This is not about getting rid of an old computer. We want usable equipment.

It may be slow, but it's perfectly usable.

My guess is it is usable, but we won't leave it.