when i was selling olys rather fast,,years ago,,thats the same thing i told the people..id told them,to put green paint on one chain, and yellow paint on the other chain, no paint on the other chain links,,and rotate them any way you want,,just keep it the same..spares in woods,,and three times the sprocket life!!!!!!!!!!!Lots of ways to do things.
I always take 3 chains per saw, so if I hit something, I can swap out the chain, go back to work, and fix the chain later. Filing in the field is good to bring back an edge, but can be a lot of work for a rocked chain, and doesn't do anything for one that breaks.
Companies like Oregon and STIHL also caution about putting a new chain on a worn sprocket, and vice versa, due to accelerated wear. They recommend rotating between 2 - 3 chains then replacing the sprocket when you buy new chains.
Philbert