I'm doing a monthly backup for my Nokia E71 phone this morning. I should have done this in monthly interval, but since i was too busy last month and Nokia PC Suite is only available to Windows, i have to reboot to Windows or else i would have to use VMWare, which is very slow in operation to backup around 800 MB of my data.
Doing a backup is very important as it might saves months of works when your cellphone is stolen or gone. This happened to my sister who has just lost her BlackBerry in Jakarta. She didn't backed up her data to her laptop, so when the BB was gone, she had to ask for contacts to all of her colleague and business partners.
Doing backup will take few minutes of your time, but it will save months or years of your works