The how much is a difficult question because it depends a lot on the battery design, chemistry, and its integration. The battery degradation chemical reactions

The how much is a difficult question because it depends a lot on the battery design, chemistry, and its integration. The battery degradation chemical reactions is mostly based on the voltage (state of charge) and the temperature. The higher the voltage and temperature, the more the “bad” chemical reactions will happen. An always connected laptop is the worst because their BMS (battery management system) are usually shit, the battery is always at a high state of charge, and very warm from the cpu and gpu. It’s a bit better on a phone. It’s much better on an electric vehicle with a proper BMS and active cooling/heating.