It would be silly not to unless you want to change rim model.

They last pretty much indefinitely when properly stress relieved and not damaged by a thrown chain, with one extreme documented example being Jobst Brandt's 300,000 mile set of 15/16 gauge spokes and hub shells.

Relacing is also slower than undoing the nipples down to the last few threads, taping the next rim to the old one in a few places, lubricating new nipple sockets, transferring spokes one at a time taking the opportunity to re-lubricate spoke threads, removing the old rim, and then tensioning as you would with a completely new rim (no stress relieving is necessary because the spokes retain the same positions).