How long can an external 3.5 harddrive be left on to continuosly transfer files?

I have a segate external from 2006 that has around 400gb of data I need to transfer. It gets noticeably hot after prolonged use and I'm worried the few hours it'll need to be on to transfer the 400gb will be too long for it to operate safely. So I plan to split up the transfer over a few sessions. How long would it be safe for an external harddrive to continue transferring data for?

Also, would it be faster if I transfer old external to my laptop C: drive first, then to a new external? Or transfer from old external to new external thru laptop directly?

 

Download CrystalDiskInfo and monitor the drive's temperature as you transfer the files, you can got at it with multiple smaller transfers if you want, but as long as the drive doesn't reach over 50 Celsius, you'll be fine. Over 50 is what I'd consider the danger zone and you don't want to get there, at over 60, I'd be really worried about damaging the drive in the long term. It's not a matter of the drive getting hotter, it's a matter of how hot it gets.

 

Until it breaks

That is seriously the answer, some drives can run 24/7 others maybe wont handle it esp if the enclosure is not made well for venting.

 

Theoretically forever. Above 55 C is where temperature might start to concern me. But it shouldn't get that hot, in theory.

Not to say it always works this way. I had a 3.5" Western Digital external drive that would spontaneously disconnect after 30 minutes or so. But that was because WD's external enclosures were poor quality, not because the drive itself had an issue.

 

Drives can be left on permanently. There is nothing to worry about unless the drive is already dying.