I am looking for a replacement desktop for wifey. She saves tons of pics & videos (she's the family photographer), and she is maxing out a Tb on her documents partition as it is. Most computer makers on their sites, only offer up to 2 tb hard drives; I was hoping to get 4. I'm wondering--would it be wise to simply get an external drive, and not use it as backups (like I do the external drive that I already have), but keep it plugged in to the desktop 24/7? I am thinking of using the external drive as the documents partition, and then the SSD that the desktop comes with, would be the OS drive. Would that end up shortening its life at all (as in, constantly having read/write cycles onto the external drive)?
Keeping external drive plugged in to desktop 24/7
- Thread starter paulri
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you sound like a candidate for a NAS (network attached storage with RAID mirroring), or if it suits your household---a cloud storage plan.
Typical mechanical hard drive is designed for 5 years lifespan (data retention, mechanical wear and tear, etc) and warranty for 1. It does not wear out much more just because you plug it in and power it on than not (data center duty cycle is different and they do wear out more based on statistic I see). Regarding to SSD, the lifespan is typically due to writing (programming and erasing) and keeping it powered will not wear it out more. They are rated for however many drive write cycle total in its life.
I found that my HDD and SSD lifespan are more random than not. Some dies within 2 years and yet others lasted 15 and still going.
MTBF is only for measuring random failure due to design and manufacturing defect (infant mortaility). You can run 1000 drives for 1000 hours and get 1 failure, and call it MTBF 1 million hours. It does not mean the drive will last 1M hours before failure. Accelerated wear and tear would be more accurate, but most base their claims on historic data like warranty claim, and customer feedbacks from data center and OEM.
I found that my HDD and SSD lifespan are more random than not. Some dies within 2 years and yet others lasted 15 and still going.
MTBF is only for measuring random failure due to design and manufacturing defect (infant mortaility). You can run 1000 drives for 1000 hours and get 1 failure, and call it MTBF 1 million hours. It does not mean the drive will last 1M hours before failure. Accelerated wear and tear would be more accurate, but most base their claims on historic data like warranty claim, and customer feedbacks from data center and OEM.
My computers are on 24/7. My system mirrors yours. Internal SSD drive holds OS and programs. 2Tb external HD drive holds all my work. Second 1TB external HD drive holds backups for everything. Been doing this for years without problems (so far).
Think about all the data center servers running 24/7. Yours won't wear out as fast as theirs will. Sound to me like you need a RAID.
Data center drives are designed differently (i.e. helium filled, seek algorithm, power stability, temperature, etc). Raid is not a replacement for backup. You still should have a backup off site periodically in case the place burn down or lightning / flooding etc destroy all the drives side by side next to each other.
Offtopic; the Seagate Exos are built like a friggin tank. I ordered 6 of them for a Synology at work and these things will absolutely do some damage dropping on somebody's foot.
There’s some little things that can get you with external USB HDDs. Try to get SCSI over USB, aka
USB attached SCSI.
To benefit from UAS, you need:
Several years ago enthusiasts kept track of which enclosures had WD SATA drives inside them; you could buy one for less money than WD was selling the internal HDDs, then crack them open and throw away the rest. Some even RAID-0 two HDDs to get to a larger size.
I wouldn’t worry about 24/7 operation. It’s more about what to do 4 or 5 years down the line.
USB attached SCSI.
To benefit from UAS, you need:
- UAS-enabled enclosure/adapter: The bridge chip inside the external drive enclosure or adapter must support UAS.
- UAS-compatible drive: The drive itself (HDD or SSD) needs to be able to communicate using the ATA/NVMe protocol that the UAS bridge translates.
- UAS-compatible USB Host Controller: Your computer's USB controller (often part of the chipset) needs to support UAS. This is standard on most modern USB 3.0 (and newer) controllers (e.g., Intel's xHCI controller).
- Operating System Support:
- Windows 8 and later (including 10 and 11) have native UAS support.
- macOS 10.8 (Mountain Lion) and later have native UAS support.
Several years ago enthusiasts kept track of which enclosures had WD SATA drives inside them; you could buy one for less money than WD was selling the internal HDDs, then crack them open and throw away the rest. Some even RAID-0 two HDDs to get to a larger size.
I wouldn’t worry about 24/7 operation. It’s more about what to do 4 or 5 years down the line.
I worked in Xray field in the early 80's and had a Special Procedures room that had an AMPEX hard drive that weighed around 200 lbs. Most unreliable drive I ever saw. Never could order just one cause they were all repaired.
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- Jul 19, 2025
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Computer people debate this all the time. Do you leave it on forever or only plug in as needed.
In my experience over years, the power cycling tends to have more more of an effect on a device than the constant power.
But, if you don't use it for a couple of months, do you really need it on still?
There is no right answer unfortunately. I think that it would be a question of how often you are using it for backups. Also, after 2 years, I would replace it just in case.
In my experience over years, the power cycling tends to have more more of an effect on a device than the constant power.
But, if you don't use it for a couple of months, do you really need it on still?
There is no right answer unfortunately. I think that it would be a question of how often you are using it for backups. Also, after 2 years, I would replace it just in case.
