Multiple pieces of equipment = multiple chances of failure. I try to reduce my chances in those cases, not increase them. I know some people like redundancy. I don't. Too many variables already, I don't need to contribut to it. I do however have backups to most of my life support equipment (replacement return pump, skimmer, heaters, bulbs, etc.) so in the event of failure, my system is off line only as long it it takes me to switch something out in lieu of waiting on something being shipped.