i have mid 2012 MBP 13" non retina. is it ok to leave my MBP plugin all the time? or do i need to unplug it everytime it reach full charge... (im doing this, unplug when 100%) i calibrate my mac once a month. i charge when im at home but sometimes when i need to go out with my mac my battery sometimes at 30% so i need more battery. so im thinking charging it when im at home. thanks in advance.