so what counts for 1 battery cycle? And why some people have 500+ cycle and have 87% health and my Macbook only had 242 cycles but with 84% health? Do i have to replace the battery after 300 cycle or i could continue to use the battery?
First, it depends on which model MacBook you have and which battery you have. Also, it depends on how the battery was treated.... whether it was left plugged into AC power for long periods or regularly exercised. There are many, many factors that contribute to battery health and the life from a charge.