Custom mail check interval in Mail App on OS X? I've already disabled "IDLE Command" so it won't push emails as soon as they arrive in my IMAP (Google Apps). I have set my mail check interval 1 hour (the longest available).

I can close my Mail App after finishing with my email routine but I sometimes forget that.

Is there a plugin or a command line script to extend the 1 hour mail check interval to, say, 3 hour or 4 hours.
You could use the following command in Terminal (or add it to a shell script).

defaults write com.apple.mail PollTime 240

Where 240 is the time in minutes (i.e. 4 hours).