The statement confuses me. The question marks confuse me. I think not starting Aguero from time to time would help him stay fit for longer. Like the other guy said, I'd be tempted to start with the Bone.
I don't see why there should be a problem playing Aguero once a week at this time of the season. If there are concerns over fitness/injury wouldnt it be better to give him a mid winter break, a couple of weeks off in Dec/Jan?
Leaving Aguero out would give Everton a huge boost.