If, say, your entire office burns down due to an electrical fire from a photocopier next door, off-site backups are worth their weight in platinum. If you don’t believe me, just look up how much professional data recovery services cost and compare that to the weight of a hard drive or fifty. Some people use e-mail as a back-up system, but it isn’t really appealing as a long-term, scalable solution. Amazon’s S3 provides variable pricing and is scalable, but may be overly complicated for backing up small amounts of data. Some off-site back-up services such as Backblaze are great deals for people with large storage needs ((I am not affiliated with or endorsing Backblaze. I just find their blog posts interesting.)).
Musings of a happy scientist