Accidents happen, storms happen, even fires happen. We can't always avoid these things, but we can plan for them. Your animals and possibly your home are at stake so good planning is a must.

• Make sure everything is properly wired and used within widely accepted norms.
• Make sure a cat, escaped reptile, or vibrations cannot knock over heating devices such as lamps. 
• For especially valuable or rare reptiles, do not rely on a single thermostat. All electronic components will eventually fail and there is no way to be sure when it will happen. However, it is highly unlikely that two thermostats will fail at exactly the same time. Room heating systems should especially be controlled by two thermostats to prevent loss of an entire room of livestock.
• Working smoke detectors should be present and tested regularly.
• Many devices can send alerts when high or low temperatures are encountered and these devices should be used when a large number of animals are present.
• An alternative means of heat should be available to tropical reptile keepers in the North. Possibilities include space heaters in case the gas line goes out, propane heaters in case the electricity goes out (larger areas probably need more powerful, direct vent systems so plan a head), or whole home generators that can automatically start-up. Whatever method is chosen, be sure to test it periodically to make sure it is in good working order should you need it. Those with smaller collections may simply be able to relocate the animals to a friend or family members home, but for large collections such an endeavor would not be practical.
• Be careful how much information you provide about where and what you keep, reptile related thefts are not uncommon. A security system and camera may be a good idea for those with valuable collections.
• All newly acquired reptiles should be assumed to have external parasites. Before entering the main collection, it would be a good idea to research mite treatments and proactively give at least the minimum treatment. Alternatively, if you are keeping a species thought to react badly to chemical approaches, predatory mites can be used.
• Quarantine: Everyone talks about it and you really have to do it. There are a number of viruses and fungi that can weak havoc on your collection and ruin everything you have built.  Most of us do not have a separate building but we can at least use a separate room or even a closet of another room.