The Li-Ion battery does not have any memory issues any longer but there is a limit on the number of cycles.
Knowing how many charge cycles your battery has and how many are left can help you determine when a battery replacement is required.
Follow these steps to access information about your Mac notebook battery, including its cycle count:
Hold the Option key and click the Apple menu. Choose System Information.
Under the Hardware section of the System Information window, select Power. The current cycle count is listed under the Battery Information section.
It’s best not to leave your MacBook plugged in all the time because of the limited number of cycles.
Hope this helps,