Updating Firefox and Managing Extensions
Before you start updating your Firefox browser, it is a good idea to purge unneeded extensions. I suggest you incorporate this preliminary step in any Firefox update.
Since Firefox disables incompatible extensions, you need to proceed carefully if you want to eliminate the risk of losing essential functionality. Firefox 1.5 can list the extensions it will disable in a browser update, but pre-version 1.5 users will have to do their own checking for version compatibility.
My recommended procedure for updating Firefox 1.5:
1. Review your list of installed extensions (Tools>Extensions) and uninstall the ones you no longer need.
2. Where possible, update the extensions that are important to you. This may require a browser restart. (I usually restart applications after any update.)
3. Run a check for the availability of browser upgrades (Help>Check for Upgrades). You will be informed of which, if any, extensions will be disabled by the browser update.*
4. (Optional) Back up the Firefox "profile data". A profile backup preserves a copy of your bookmarks, preferences, passwords and other important browser/system settings. Before you skip this optional step, please consider the work involved in recreating and entering your data and program settings. (I am looking for an authoritative how-to reference for a Firefox backup procedure, and will update this post as soon as I find one.)
5. Update now, later or never
* Pre-version 1.5 Firefox users will need to go to the Mozilla Firefox Add-ons page and check each essential extension for updated browser compatibility. For example, see the entry for ColorZilla.