Backing up your data is very important, and most people will just procrastinate on the matter until its too late.
Backing up your data is easier than you think, and a small investment of time will keep you from ripping your hair out when your device decides its time to quit.
I can't think of a better example than myself. I am an IT student at a local college, that means Word documents, Powerpoints, txt files with notes in them, visual basic code, and other stuff like digital copies of teacher handouts.
I carry an 8GB flash drive almost everywhere I go, and it has my entire college career on it. Old stuff, new stuff, it doesn't matter, because I rest easy when the data is on hand.
Everyday when I get home, I plug in my flash drive, and right click my college folder, and tell it to go to my documents, both on my Big Rig, and on my netbook.
this is my third flash drive. I've lost one at school, and another to the washing machine at home.
I always have a spare on hand, even if it is smaller than 8GB, so that I can recover from what would normally be a disaster without much trouble at all. that kind of data integrity is a must have for a student.
Lets say your backups are of data for a business....
For example, you and three others have spent the last two weeks using adobe to take footage of an event from three different sources, and a dedicated audio track to make a DVD.
But a hard drive has decided its done, and takes all that work with it, all those Man-hours spent, just to be wasted.
Get an external Hard drive, and some blank DVDs, and make sure that the chaotic world of technology doesnt catch you with your pants down.
Enough of this long winded rant.
TL;DR : Don't be lazy. Backup your data now for peace of mind later.