When looking for storage media, we're not short on good options. So whether you want large capacities, superfast performance, or portability, there's a perfect choice for you.

But just how reliable are these different media? We know that CDs and DVDs don't last forever. What about hard drives and solid-state drives? How long will they continue to work on your computer, and how long will they store your data if you use them for archiving?

Let's look at how long your drives will last and whether an SSD or HDD is best for long-term storage.

Hard Drives

It's well-known that deleting files from a hard drive does not mean that they are gone forever. From time to time, security experts will collectively collect drives from discarded computers purely to demonstrate how much data can be recovered from them. It's normally a startling amount. In fact, the only way to be sure your data is gone is to destroy it physically.

A shattered hard drive
Image Credit: techmsg/Flickr

Unfortunately, that doesn't mean that a hard drive is a reliable long-term storage device.

A hard drive relies on a series of moving parts—a spinning disk that's read by a moving arm with a magnetic head. Like anything with moving parts, it will break eventually.

Hard drives are prone to suffering a head crash, where the head touches and scrapes across the disk. This can be caused by all manner of things, from a power cut or surge to physical shock to a manufacturing defect. With regular use, a head crash, or other physical failures, will be the reason you need to replace the drive long before any other form of degradation sets in.

In a crunch, you can attempt to repair a dead hard drive to recover data. A 2021 study by cloud storage company BackBlaze looked at over 200,000 disk drives and found that for the first three and a half years, around 2 percent of disk drives failed, most likely due to manufacturing defects. The report reveals that 90 percent of the drives lasted for four years, but only 65 percent exceeded the six-year mark.

A hard disk.

Besides, according to the report, the life expectancy of hard drives decreases at a stable rate of 2 to 2.5 percent for the first four years, after which the rate increases at an increasing rate which results in only 65 percent of hard drives surviving by the sixth year. If the drive is unused—if you were to copy your data to it then store it away—you can reasonably expect your data to last for many years.

A hard drive stores its data magnetically, and as long as you keep it away from another strong magnetic source, it is fairly stable. The magnetism can diminish over time, putting the data at risk, but this can be restored by powering on and reading or writing the data. You should do this every few years if you're using a hard drive for long-term storage.

Related: How to Connect and Get Data Off a Hard Drive

Solid-State Drives

A solid-state drive doesn't contain the moving parts of a hard drive. The spinning platter (the disk), the arm, and the magnetic head are absent, and flash chips are used in their place.

This means an SSD is not vulnerable to head crash in the way that a hard disk is. In addition, the added durability gives the SSD an obvious reliability advantage, especially when it comes to shock or exposure to less than optimum environmental conditions. They're also not affected by magnets.

Close up shot of a solid state drive
Image Credit: Ambra Galassi/Flickr

However, it's worth remembering that the other components in an SSD are the same as those in a hard drive and are no more or less likely to fail. SSDs are also extremely susceptible to power failure, leading to corruption of data or even the failure of the drive itself. With solid-state drives still being in their relative infancy, it will likely be a few more years before we get a true picture of how well they hold up to repeated use.

The lifespan of each memory block in an SSD is limited to a certain number of write cycles, which means the number of times a piece of data can be stored to it. The number of cycles will only be a few thousand on most drives. This sounds alarmingly low but is not really an issue in modern SSDs. Unlike hard drives, which write their data to the earliest free block, an SSD uses a technique called wear-leveling to ensure that each memory block is used before the cycle begins again at the first block.

Unless you're writing tens of gigabytes of data a day, every day for several years, you won't get close to the limit on write cycles. Even if you did, the memory would become read-only, so your data would still be accessible.

Circuit board of SSD close up

All this means that SSDs are a great choice for day-to-day storage over HDDs, so long as performance is a bigger priority than capacity, given the relatively higher price of a solid-state drive.

But is an SSD good for long-term storage? That depends.

The failure rate of SSDs largely depends on the technology used and how you use them. Generally, SSDs are expected to last longer than HDDs for general use cases. However, how long an SSD can store data without power depends on several factors, including the number of write cycles that have been used, the type of flash memory used in the drive, the storage conditions, and so on.

Joint research by Google and the University of Toronto reveals that SSDs were replaced 25 percent less than HDD over a multi-year period. The research also notes that 20–63 percent of drives experience at least one uncorrectable error during their first four years.

Related: Things You Need to Consider When Buying an SSD

But while the longevity of SSDs is not so clear, many SSD manufacturers will list data retention either as part of the specification or the warranty for their drives. For instance, Samsung's 250GB 860 EVO SATA SSD is promised to withstand at least 150 TBW (Terabytes Written) or five years, whichever comes first. The JEDEC Solid State Technology Association sets the industry standard at one year for consumer drives.

Flash Drives

USB flash drives and memory cards like SD cards have similar issues to solid-state drives. They have fewer components and are far more robust but are restricted to a finite number of write cycles, usually in the range of 3,000 to 5,000. Since they tend to use cheaper memory modules, they can be less reliable than SSDs. Again, though, this needs to be kept in perspective.

If you're using the flash drive for its primary purpose of moving files from one location to another, then a cheap drive will be more likely to fail through physical damage (such as breaking the connection between the USB jack and the printed circuit board inside the drive), before the write limit is reached.

Blue flash drive being inserted into computer with white background

Equally, an unejected drive will be more likely to put your data at risk. A lack of fault tolerance can put the entire drive in danger. USB flash drives aren't a great option for archiving. Drive manufacturer Flashbay says that flash drives can withstand 10,000 to 100,000 write/erase cycles depending on the technology used.

As with SSDs, data retention is affected by the health of the memory blocks. A flash drive bought specifically for backing up files and storing could last for many years; a heavily used drive could lose its data within months if left unpowered. If you are interested in purchasing a flash drive, check out our list of the fastest USB flash drives you can buy right now.

SSD vs. HDD: What's Best for Long Term Storage?

The most important thing to remember when looking for storage media for backup is that nothing lasts forever. You can expect a storage device to keep hold of its data for a couple of years if it goes unused. But you should also regularly check the drive and that the data is still intact. Copying the data off the drive and then back on will ensure it extends its life for a few more years.

Of course, the only reliable backup solution is to make two or three backups and rotate them periodically.