In the past before OS X Leopard 10.5 was launched with time machine backups, we used to clone our hard drives with CCC or carbon copy cloner.
It was straight forward as easy, just plug in an external hard drive and the software could be set to automatically run. While it does provide a backup should the laptop go missing or damaged, it is not considered a proper backup solution as there is no way to retrieve accidentally deleted files.
Having upgraded to OS X Leopard 10.5, we purchased a new external maxtor 500gb hard drive as a time machine backup drive. Without reading the documentation and how time machine works, I just plugged in the external backup drive.
Apple products always emphasize ease of use and this is no different. I was immediately prompted if I wanted to use this external hard drive as a time machine backup. After clicking okay, the backup started.
When the backup was completed, the hard drive was unplugged from the MacBook Pro and plugged into the MacBook. The process was similarly simple and all went well.
Since all the macs are on the same wireless network, I decided to try and mount the backup drive still connected to the MacBook on the MacBook Pro.
The surprise here was that when I tried to run the time machine backup, an error message indicated that the file system was not Mac OS Extended Journaled. I disconnected the external backup hard drive from the MacBook and connected it to the MacBook Pro directly and time machine worked.
I guess time machine backs up differently when connecting the hard disk directly or through wifi. So before you decide to start using time machine on a few macs, remember this and I hope it helps you avoid repeating the lengthy backup process especially after accumulating years of digital photos and music.