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I typically drive less-than-20-minute of local roads between my home and office, during which I usually keep my Macbook Pro closed but powered on and in a backpack in back seat. Is it harmful to its hardware? If so, how and how much harmful?
I am trying to decide if it's worthwhile to take a few minutes to power it off properly daily before leaving office or doing it is virtually meaningless.
.... and now, a long, rambling answer...
Do I need to power off my Macbook Pro during commute between home and office? Either approach is fine. Obviously being suspended will consume battery power slowly (very very slowly). If you're going to run on battery for a while at home too, then the power cost of shutting down and booting up may end up being more than being suspended.
Is it harmful to its hardware? If so, how and how much harmful? Apple encourages people to use their machines like that. It could only be harmful if the machine is being woken up (and thus spins up the hard drive while the machine is being vibrated hard). Anything that would generally damage the machine in a suspended-state would also damage it in an off-state. Unless you're doing something really weird, it's not harmful.
I am trying to decide if it's worthwhile to take a few minutes to power it off properly daily before leaving office or doing it is virtually meaningless. I think it's a serious waste of your time to power-off. I think it also provides unnecessary (though trivial) wear-and-tear on your hard drive.
Ultimately, the practical difference is so superficial that you may as well just do whatever you 'feel' is best. If you're in constant fear of zombie apocalypses (like me), then you may be happy to know that your laptop in its powered-off state may end up having enough juice left in it, that when some survivor takes it from your corpse, they may manage to use it enough to solve some key problem and save humanity.. All because you left the machine in a state that left the battery charged. Not that you'd ever get props for it. If you're like me, however, you'll just suspend the machine and let the rest of the human race fall with you.
If you are not using something like 'Caffiene', or some other 3rd-party tool to keep the MBP (Macbook Pro) actively running while it is closed, your MBP should enter stand-by within a minute or so, when the lid is closed to put into your backpack.
If the MBP is in 'stand-by', the HDD will not be spinning and is therefore very safe to transport. However, some software may, intentionally or unintentionally, keep your MBP from entering stand-by mode. If that happens, though, all hope is still not lost.
Looking at the specs for a typical 2.5", internal HDD these days yields the following:
Environmental (operating) Shock (half-sine wave) 400 G/2ms, 225 G/1ms
Environmental (non-operating) Shock (half-sine wave) 1000 G/1ms
The first thing to notice is that the limit is lower for a shorter impulse. This suggests that the drive is more sensitive to a sharp physical shock of short duration than to mild acceleration (typically < 1 G) as may be experienced on your daily commute.
If your backpack provides any padding, and you are careful to place your backpack on your floor, where it can't slide off the seat and hit the floor, it should be fine even if it is still running. But, if you are walking out and smack your backpack into a wall or doorframe on your way, the risk is much higher.
Even at the higher risk, though, the real risk is pretty low. Imagine the impact necessary to damage the drive while it is off. The shock it would take to damage it while running is still greater than 20% of the non-operating shock tolerance. That is a pretty significant shock.
For the record, I never power-off my MBP, but it DOES go into stand-by before I bag it.
I hope this helps!
