Quarantine tanks are important. They help with the pretreatment of any kind of potential problems with fish or corals before they become a threat.
They shouldn't be hard to maintain at all if not in use. A simple setup of some sand, a heater, thermometer, PVC pipes, and anykind of filter without the use of carbon will work. No skimmers needed.
Quarantine tanks for inverts should be different from the quarantine tanks for fish. Medications can kill your inverts.