2008 jeep wrangler unlimited rubicon, when should I take off overdrive?

leaving the over drive on saves more fuel. it slows the rpms down and shifts the transmission into a lower gear, making the engine use less fuel. usually, overdrive is turned off when more torque and better, faster acceleration is needed/used, usually for towing

Overdrive is also useless for speeds less than 45mph and will cause your transmission to have to shift in and out of overdrive an excessively high amount. Typically it is suggested if you're not on a highway or interstate or etc then turn overdrive off to save wear and tear.

these trannys dont have the same issue that the GM 4l60 does. Put in gear and drive it.....