I rotate them based on their grinding, moving from the wedges, 1/4 half, 1/2, full, extra hollow and back up towards the wedges again.
I don't think it's a particularly "intelligent" rotation but I used to find switching from a heavy Sheffield near-wedge to much lighter grinds a bit strange. This way it's more gradual and I don't really notice the change.

Stragely though, every now and then a particular razor demands to be used when it's not its turn!