Do Proportioning Valves Wear Out?

We cant know a used valve is good without trying it. If I pull a working part and carry it across the shop and install it on another, I would be disappointed if it died in transit.
Most of the members here are dealing with parts that came out of the mail box, junk yard, dusty shelf where it has laid for several years, D; all the above.
Would I bother to install such a part ? That depends on what part it is. A rear end ? maybe, A power window motor ? No A brake fluid related part ? No.
Especially not the most difficult to R&R of them.