Discovered two useful tricks recently, one for Thunderbird and one for Firefox:
Thunderbird: If you are using IMAP, messages may take a few seconds to appear, which if you frequently look back through old messages, sent messages, or just keep messages in the inbox to be dealt with at a later time can unnecessarily slow down the process. Enabling offline use for your folders (“Tools” > “Account Settings” > “Offline & Disc Space” > “Select folders for offline use”) means that after an email has been viewed once, Thunderbird will keep it cached on the local hard drive meaning that pulling up that same messages again will be much quicker.
Firefox: If you have multiple e.g. Google Mail accounts, and would rather not keep signing into / out of each, or would like to have multiple accounts open at once you can use Firefox profiles. Each profile is completely separate (bookmarks, cookies, etc). This is also useful if you have multiple clients, you can create a separate profile for each and therefore avoid the need to keep logging in and out of e.g. Google Analytics and any other web services for each.
Close all existing Firefox windows, and launch Firefox with the “-ProfileManager” argument. This can be done on Windows by pasting “firefox -ProfileManager” into “Start” > “Run”. Then create all the profiles you need. After you have created the profiles, create separate shortcuts to launch each by first copying your existing Firefox shortcut from the start menu, and then editing it (right click, “Properties”) and adding -no-remote –P “ProfileName” to the end of the “Target” box for each profile you created. Then simply double click each created shortcut to open a new Firefox browser window with that profile. Further information can be found at mozillaZine: Command line arguments.