I went out to my truck and grabbed my 25 yr old maglite. I'm not sure when I last changed the batteries and not sure when I last used it. It's not even strapped down, it rides between the
seat and the fire extinguisher.
Turned it on and it works.
Most of the flashlights around the house are Harbor Freight or HF knock-offs (is that even possible?).
My Blue Top Optima is 8+ years old, bought it used 6 years ago. It lives in my trailer where it's fully charged before a trip. It powers the fridge, camp lighting and usb chargers. Recharged by 200w solar during the day. Sometimes I charge it before storing the trailer. Still kicking.