This is a common situation, I think.
Seemed like every year I'd be pulling tires off the FJR that still had a couple thousand miles left on them (in dry weather, or by SkooterG standards), yet because I was heading to BFE in the monsoon season, or out on a long ride that I didn't want to be stressing about my tahrs, I'd swap it 'em out and throw the old worn tire(s) on "the pile". Well the old tire pile grows continuously taller every year, until they get age checked and hauled to the town dump, as I am less wont to put an old tire with only a couple thousand miles left on it back on vs. just ordering a new skin.
But... if it were still mounted on a perfectly fine and previously balanced wheel, well... I'd swap the wheels in a jiffy.