Not necessary if the air is dry inside the headlight. If the headlight is properly sealed, yet the air inside the "sealed" headlight has high humidity it will still condensate. Dive watches are properly sealed, yet will fog if temperature changes quick enough to separate moisture from air. I would recommend throwing in a dessicant pack if you are concerned about condensation. I never had a problem with Ed's headlights when I owned them, went to OEM HID; neither have had a problem with condensation here in the high humidity Northwest.