One of the most common misconceptions about solid-state drives (SSDs) is that they’re capable of storing data indefinitely. All storage devices eventually fail, and unfortunately, SSDs are no exception.
That doesn’t mean that they’re unreliable — SSDs offer much faster data access than hard drives, and they’re less susceptible to physical damage. A modern SSD can operate for upwards of 5 years under optimal operating conditions. However, the way you use your solid-state media will determine its lifespan, and external factors can certainly play a role.
Solid-State Media is Reliable, But Not Perfect
Every digital storage device has drawbacks, and while SSDs are reliable, they can still lose data under certain circumstances. In fact, all SSDs have an expiration date — but figuring out that expiration date requires some complicated math.
Here’s a basic overview: Solid-state drives typically use NAND flash chips, which are functionally similar to the chips in USB drives and flash cards (such as SD or xD cards). Hard drives store data through magnetization, but flash media devices read and write data by electrically charging cells. That makes them much faster than standard hard drives, since they don’t need to move mechanical components to read or write data.
Of course, there’s a downside to this approach. Over time, the cells that store the electric charges become less efficient. Eventually, they’re unable to hold the charge reliably. Flash drives use a technique called wear leveling to ensure that data is written evenly across the cells, which prevents individual cells from receiving too much of the work. Even so, every solid-state device will eventually become less reliable as cells wear out.
Solid-state drives can also fail for other reasons. Electronic damage can prevent the drive from operating properly and damage the firmware, rendering it unusable. Malware attacks, file corruption, and accidental file deletion are other common causes of data loss.
SSD Lifespan is Determined By Usage
The more you use your SSD, the less reliable it becomes. The good news: Wear leveling and other technologies have dramatically increased the expected operating lifespans of flash devices.
So, how long can you use an SSD before considering a replacement? While product warranties aren’t a great way to measure actual operating lifespan, they do provide some insight for SSD reliability. SSD manufacturers list total terabytes written (TBW) in their warranties, along with a traditional timeframe; if the user writes a tremendous amount of data to a solid-state drive, their warranty will expire.
The Samsung 850 EVO, for instance, has a limited warranty of 5 years or up to 300 TBW. The data warranty policy changes depending on the size of the drive, so larger drives usually have a longer TBW period. You’ll need to determine how much data you write on an everyday basis to make a reasonable estimate regarding lifespan; if you’re using your SSD as a media drive, for instance, it’s likely to hit its rated TBW fairly quickly, but if you don’t regularly write much data to the device, it may last longer.
This doesn’t mean that a Samsung SSD will immediately fail after surpassing 300 TBW. Many drives last for much, much longer, but generally, SSDs will begin encountering issues after about 5 years of typical use.
Are SSDs More Dependable Than Hard Drives?
Yes and no. In theory, hard drives can read and write data any number of times without failing. That’s not true in practice, however; the moving components of a hard drive will wear out over time, eventually causing failure. On average, commercial hard drives have a rated lifespan of 3-5 years. Many hard drives last much longer (and others suffer head crashes or other catastrophic failures after a few months of use).
Solid-state drives don’t store data via a mechanical process, but they’re susceptible to electronic damage. As we’ve discussed, they also have a limited lifespan — the more you use an SSD, the less dependable it becomes.
Depending on the user’s behavior, an SSD may be more reliable than a hard drive, but the opposite is also true. If you access your storage media constantly, a hard drive might offer a slight improvement in long-term reliability. Of course, we haven’t discussed dozens of factors that could affect storage media lifespan.
The takeaway: All storage devices have drawbacks, and you should never consider your data “safe” if it exists on a single physical device. Make regular backups of all important files, regardless of whether you’re using an SSD or HDD as your primary means of storage.