It has been ON for years ands years and at pretty high brightness. It has never been OFF. Not ever touching the setting has been very cool. I realized yesterday that it should be replaced, so I swapped it for a new lithium AA made by Duracell. The Duracell ProCell batt that I pulled out (which has been kept ON for YEARS) had an expiration date on it of MAR 2018. DAYUMMMMMMM I think that is doing pretty durn good for one AA battery. That is all. Now continue with your normal conversation.