Firefox and Thunderbird have their fans, and I count myself among them. I've been burned every now and again by instabilities in these apps, though. This time, I suggest a utility that makes it easy to protect your profile data.
Firefox is the browser that I recommend for daily use. I've found it to be more standards-compliant, and its open-source transparency makes it more secure, in my opinion. I've also been really pleased with Firefox's stability overall. Sometimes, though, even the best tool can fail you.
I've had upgrades to Mozilla's programs go wrong, leaving me with broken profiles, and crashes can sometimes leave personal data inaccessible. Firefox's developers have tried to address this by building in an automatic backup for bookmark files, but I like to take the safety of my data into my own hands. To augment my existing Windows backups, I use a specialized utility to make sure that I regularly provide additional protection to the Mozilla programs I use.
MozBackup, a freeware utility developed by Czech Pavel Cvrcek, provides a simple interface to backup and restore the profile data stored by the major Mozilla programs: Firefox, Thunderbird, and SeaMonkey/Mozilla.
MozBackup allows you to select any profile in the Moz program of your choice and then back it up to an archive that you can store anywhere. You can also choose to restore an existing archived profile to your installation.
The customization options for your backup archives are pretty extensive. You can choose to protect your extensions, or exclude specific files so you don't waste space backing up your cache files, for instance.
I've used MozBackup to gracefully move profiles between computers, and to provide additional backup flexibility to those users who need to use multiple Firefox profiles in one Windows account. If you develop add-ons for Mozilla's products, you really shouldn't try and live without this utility. My suggestion: set up a weekly Scheduled Task in Windows to launch MozBackup on Friday before you go home for the weekend.
Now to be clear, it's certainly possible to backup and restore your Mozilla programs' profile data by manually copying files in the Windows Explorer. You could also selectively restore profile data from your existing backup solution. It's possible to screw things up by manually copying files, though. If one neglects to copy in the key database when moving files around by hand, that can leave the user's saved sign-on file inaccessible. MozBackup takes care of making sure that the proper files are archived and restored based on your selections in its wizard.
Hopefully, you're all regularly backing up your Windows data already. MozBackup makes it ridiculously easy to create a special data security workflow for your Mozilla programs. Given how much I rely on their apps, I like having both a belt and suspenders.