It really depends on your type of data, if it's sensitive data or not. And it also depends on what type of backup (Incremental, Decremental, etc.). But you should aim to backup at least once a week, and also do a backup of your original backup.
Answer:
When it's too hot or too cold.
Explanation:
When a bulb of the wrong size or voltage is used in the fixture, the ballast often overheats, causing the light to shut off. The bulbs and the fixture must also match in frequency, or the ballast becomes overworked and overheated.
