I bought my Mac Keyboard, Logitech K 750, in May 2016. For the first time ever, the keyboard shut down at the end of 2019, totally dead. To keep it alive, I kept charging it daily, and it was hanging in there with about a 30% recharge. We installed the new ML2032 battery last night (amazon), and this morning, keyboard charge is in the Green Zone for first time in months. I'll be putting it in the sun later today for full charge. So far, so good, and we used eyeglasses screwdriver to open the battery slot. Didn’t cut the tabs - figure one change in 3-1/2 years we can deal with it being a little tricky.