Well, I rotate my MT tires every 10K miles my truck has 334K miles, its a 2002 Tacoma and I am running on my 3rd set of tires, 6 Wheels ( 2 spares tires )
on my cars, I do every 10K miles every oil changed !
I would wear thos 2 tires and buy 4 new tires but just remember, rotate rotate rotate...