Which is better for the long term life of my MacBook Pro battery? A) Using the laptop mostly plugged in when I am able to plug it in. B) Using the laptop without it being plugged in and only plugging it in when the battery runs low? I mainly use my laptop on my desk where it's no problem to have it plugged in, but I just want to know is it bad to have it plugged in all the time or what? Cheers.