I don't know what is best. I'm far from a processing expert. If you don't mind the delay for a followup shot, leave it on. Whether its on or off, you will still have to do some post possessing and you will still have 'regular' noise depending on scene and exposure and iso. The LENR should remove any hot pixels and other noise that results from the sensor warming up. I've not experienced a noticeable problem with long exposures, so I can't really describe the type of noise it removes. Now I'm curious and I'll have to experiment. My night shots are usually 10 seconds or so and I really don't think it is detectable in that range. Maybe on a 30 second exposure in the black of night, you might see an improvement.