Rated 4 out of 5 stars

I started using Thunderbird having been used to GMail's web client, and was used to the "Undo send" function. I set up Send Later to give me a button that sends my email in a minute's time, which is usually enough for me to realise I've put the wrong person in the To: box or realise I wanted to add some more text. Very good! The only reason I've gone for 4 stars rather than 5 is that I'd like to be able to do this "send in a minute" from the Ctrl-Enter keyboard shortcut, but it's only a small issue.

This review is for a previous version of the add-on (5.0). 

See the user guide: http://blog.kamens.us/send-later/#blunderdelay