If you don't back up your databases, memorize this phrase: "Do you want fries with that?" It will come in handy in your new career.
In this age of reliable, redundant hardware the need for backups is often questioned. Unfortunately, redundant hardware only protects against the failure of that hardware. You can still experience data loss due to user or administrator error (yes, sooner or later even database gurus trash a database), corruption, malicious data destruction, or disasters such as fire. I like a backup plan that passes what I call the Scud Test. If a scud missile were to land in the server room, could you still restore the database? One sure way to answer yes to this question is to have valid backups, stored offsite. It is surprising how many mission critical databases do not pass this test. You can substitute fire, theft, flood, or earthquake for the scud missile; pick the one that applies to your locale!