What is main difference in a portable external HDD and a regular external HDD? I have an external 3 TB WD drive for backup. I think it is shot so I want to replace it. I don't need a portable drive but if they are more durable I'd like to get one. The cost difference between portable and regular is negligible at Amazon. Are there any issues associated with using a portable HDD for a Time Machine backup?
There's a small difference. A portable HDD draws power directly from your computer while an external HDD draws power from a power adapter plugged into the wall. Durability will vary depending on quality. If you're using a portable device (such as a laptop) it is suggested to use a portable HDD so you don't have to plug it in elsewhere. It should also be noted that portable HDDs draw more power from your computer which may result in faster battery consumption on portable devices or worse performance on devices using a very little amount of power (such as a Raspberry Pi).