This is for a home computer. I'm going to have a drive with only data in it that will not be replaced unless it fails. So it will be there for a while. So I need a device to connect it to. Should I use an enclosure where the drive is inside a sealed case or a docking station where the drive stands on edge and is mostly exposed? The only possible differences I see involve heat and dust. If a drive is sealed inside a case it would heat up more than in a docking station but I'm using 5400 rpm drives - they're cheaper and will only store data so it's enough - so I don't think heat will be a real issue. A docking station will have more of a problem with dust. If you use a 2.5" drive, the slot for a 3.5" drive is covered by a piece of plastic. If you install a 3.5" drive, the slot where you put a 2.5" drive is left uncovered. This is based on the many pictures of docking stations I looked at on Amazon. So the 2.5" slot will end up with dust inside it. What do people usually do about this? I don't need to do any hot-swapping of drives either. So which should I use? Is there a difference in terms of lifespan between drives that lie flat in enclosures vs drives that stand on edge in enclosures vs drives in docking stations?

If it will stay connected, why not put it inside the computer ?

You could also buy an external usb hard disk, that is already closed and thus not suffers from the dust problem.