The attached mail from mr. Jobs (there is a url at the bottom) is what you want to look at.Regards, Stephan.Yeah there even research from Nokia about power consumption http://research.nokia.com/files/tr/NRC-TR-2008-002.pdf
... but this thread is about imap IDLE which is unrelated to "subscribing". I think a client must implement LSUB and SUBSCRIBE but what it does with that info - or if it uses it at all - is another question.
cheers, Jakob Curdes