It’s fine.I know people who leave theirs in 24/7. I’ve never heard of anything bad about doing so. I mean, it’s what their for, so I wouldn’t see why it would shorten the lifespan.

My home setup relies upon two external drives of 1 Tb each. The only thing I feel is necessary, is that you must understand that every hard drive eventually fails, so you must have allof that data backed up somewhere so that you can restore it when your drive’s time comes. It is generally recommended that you have at least one set of backup data store doff-site, in case of a fire, flood or other catastrophe.

I wouldn’t suggest it, but I don’t think it’s harmful to the drive.
Last time I browsed prices, internal harddrives are a lot cheaper (per gig) than externals. So if you have your external always hooked up, it’s doing the same task as an internal, but at a higher price (and slower transfer rate. USB is pretty poor compared to SATA 3.0).

I have one of those old external drives that doesn’t shutdown with the computer :(
What @pdworkin said, every hard drive fails sooner or later. Every moving part in a computer will wear out, and once it does you better have your data backed-up.

I constantly have mine connected to my computer and have done for months. Nothing bad has happened thus far.

I might be worried about viruses infecting the computer and the hard drive if they’re always connected . . . but I am surely no techie, so I don’t know for certain if that’s possible.

I have had my external drive connected 24/7 for the last 2 years , no problems i don’t even hear anything coming from it . The light was pissing me off so i magic markered over it

I didn’t want to give the impression that all of your hard disks will blow up in mere minutes after connecting it. Just so you know, mine has been hooked up for 2 years and I do occasionally shut it down, but mostly it’s on 24/7.

@efritz Yes that is entirely possible. It happened to a friend once and he infected half the western hemisphere with his external hard disk. Most viruses will copy themselves to your external disk and use the autoplay features to install itself when you hook it up somewhere else. I used Panda Usb and Autorun Vaccine to disable the autoplay features on my disk.