I dive mainly high mountain lakes. All altitude and cold water. I have had my Wisdom for just 12 months, 60+ dives, and have experienced 3 failures, one while under ice. Each time the unit fogs, then goes eratic. I have not had any luck with the Sherwood website or CDI in resolving the issue. Each time it takes 4 or more weeks to get a replacement. My dive buddy has also had the same failure with his Wisdom. Is anyone else having the same problems? And, has anyone been able to get some help from Sherwood?