Windows/Mac/Linux: Previously mentioned Thunderbird extension Send Later rolls some time-saving buttons into a neck-saving extension. Now you can pre-set delays—30 minutes, 2 hours, tomorrow—for emails you want to hold off on. Just as before, you activate Send Later (or SL8R) by hitting Ctrl+Shift+Enter, a slight variation on Thunderbird's Ctrl+Enter shortcut. When you get the prompt above, you can activate any of the pre-set delay times (chosen in the add-on's options dialog) by hitting Alt and a number 1-3, giving you a cooling off period or letting you disguise your late-night email checking. Version 1.2 of Send Later incorporates a few other fixes and goodies, including a toolbar and draft folder presence and reduced memory use. It's a free download, works wherever Thunderbird does. Note: Screenshot from developer's blog; this editor's Thunderbird loaded the extension fine, but he forgot to snap it inside a different partition.