I backup all the time. Everything that is on servers is backed up 4 times a day to another data centre and stuff on computer backed up every night to external and frequently to online.
It is the very important for me in my business because i have the more data about the people.I worked on the government data & it require the more space for storage.DVD storage is not the good for backup sometime it crashed.I think carbonite is the best of online backup storage rcovery.