Please help me understand selection of a red dot sight for a carry gun. Specifically, how do "instant on" sights turn on when you draw, and which models have that feature? Or are they really "always on?" I wanted to test red dots with minimal initial investment, so I recently put a Bushnell TRS-25 on my 10/22. A single session to zero it convinced me red dots are cool. I already have a second TRS-25 for my M&P-15 Sport, just waiting for the Piccatinny riser to install it. That brings me to my M&P 2.0 9. I've had enough advanced carry classes and pseudo-IDPA competitions to understand pausing to turn on the dot when drawing is a non-starter. The just released 4 MOA dot Bushnell RXS-250 with a list price of $250 has me intrigued. It claims 50,000 hours of battery life, but no indication of an instant on feature. The details on the linked page also claim it is designed for duty holster use. At 8,760 hours per year, that would mean a nominal 5 year battery life if left on all the time. I guess you would extend the calendar life by turning it off when not actually carrying the gun. [Side note: Amazon is asking $290 for the sight, quite a premium over the MSRP.] I appreciate any education y'all can add here.