How big of a concern is battery overcharge/running dry?

[lepidotós]

I've heard conflicting statements on whether it's important to keep between a range of battery percentages, that range being different every time I see it (90-35 last I heard, 80-20 before that), to keep from stressing the cells. I imagine there's some sort of truth to it, but I figured you all would be much more knowledgeable on that than I am.​

 

[Apple_Robert]

If your Mac is plugged in most of the time, it is best to exercise the battery once a month by allowing it to discharge to 15 - 20% left, before charging again. Leaving a battery plugged in and fully charged all the time is as bad as draining the battery all the time until the Mac turns off. If you can reasonably keep the battery around 70 - 80 charge, that appears to be the so-called sweet spot.

 

[onre]

FWIW, I've never done any of this. Despite that, batteries on all of my laptops and phones have aged really well. Phone is almost five years old and still charges to over 90 % of factory spec. That said, it's entirely possible that I have just lucked out and the battery cells in my equipment are in the top quality decile of all production.

 

[fooyork]

I know this is the PPC forum, but on your contemporary Macintoshes there is an app called Aldente that can manage this for you… I have my MacBook Pro battery set to charge to 70% and hold there, topping it up and discharging it occasionally - it’s often plugged in for long periods of time on my desk.

Aldente link