Should we reply to the editor after a paper has been rejected and we don't plan to revise/resubmit? After receiving a rejection (not revise and resubmit) decision from the editor/associate editor of a journal, should we write an email to thank him/her for the time, or just do nothing? I imagine one might do that out of courtesy, but then I don't really have much to say otherwise.
I don't recall ever having received such an e-mail as an editor, so it's not standard (let alone mandatory), but I wouldn't be unhappy to receive one.  I doubt anyone would care enough to make it worth the effort, but it could be a nice gesture if you feel inclined.