Here are some charts that show how often Macintosh users back up their data. 26% of all Macintosh users back up their systems regularly. However, only 4% make use of the auto back up feature:
Hands down, the three most eyecatching experiences with Leopard are, in no order, the new iChat moving backgrounds, the new reflective effect of the dock, and Time Machine. Apple engineers intentionally made Time Machine look this good so that people will be encouraged to back up often in exchange for the eye candy.
It is advised to purchase a “time machine” (aka external drive) that is at least equal to the total hard drive space of your current Macintosh. It is advised to run Time Machine before you go to sleep so that when you wake up the next day, the backup process would have been completed.