Well most hard drives today and more durable, usually its OK to leave them running continuously but you should definitely keep them away from other electronic devices and open ventilated area ect. Ideally a fan.
Though I dont see the point in it.. Maybe if it had a sleep feature It would make more sense to me. Download crystal diskinfo and monitor your drives through that if you're worried. This application saved me, my hard drive was nearly too far gone and ready to fail but after crystal disk info showed all of the bad sectors, I bought a new drive cloned it and saved everything before the old drive failed.
Not all drives are the same remember.