80% charge limit on iPhones - does it help save battery health?

Juli Clover at MacRumors ran this experiment two years in a row with a 15 Pro Max and a 16 Pro Max, and got the same result each year, keeping her phones’ charging limit at 80%:

• 16 Pro Max - 94% battery health after 297 cycles.

• 15 Pro Max - 94% battery health after 297 cycles in one year.

• 15 Pro Max - 88% battery health after 352 cycles in two years.

I ran a similar test and got similar results each year:

• 15 Pro Max - 99% battery health after 296 cycles.

• 16 Pro Max - 100% battery health after 270 cycles.

I would say my numbers are higher because I use MagSafe more than 90% of the time in cool environments, whereas Juli had a 50/50 mix between MagSafe and fast charging via USB-C, not to mention using battery packs while outside in warmer environments.

Heat is the biggest factor that degrades battery health, and you get the most heat with the fastest charging speeds. The bulk of my charging is in two different bedrooms that are pretty cold - one has a Anker MagGo Magnetic Charging Station (8-in-1) and one has the standard Apple MagSafe charger.

Annual phone upgraders don’t need a charge limit, unless they want to sell the phone at the best price possible with a higher battery health (yours truly). If you trade in your device each year, then don’t even worry about charge limits.