How Long Will My Mac’s SSD Last?
To work out how long you can expect your Mac’s internal SSD to last before it reaches that cycle limit, all you need do is to measure how much data is written to it, and once that is 3,000 times the capacity of the SSD, you should expect it to fail through wear. Fortunately, SSDs keep track of the amount of data written to them over their lifetime. This can be accessed through better SSD utilities like DriveDx, and I even have a feature in Mints that will do that for most internal SSDs.
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Unless you work with huge media files, by far your worst enemy is swap space used for virtual memory. When the first M1 Macs were released, base models with just 8 GB of memory and 128 GB internal SSDs were most readily available, with custom builds following later. As a result, many of those who set out to assess Apple’s new Macs ended up stress-testing those with inadequate memory and storage for the tasks they ran. Many noticed rapid changes in their SSD wear indicators, and some were getting worryingly close to the end of their expected working life after just three years.
Previously:
- MacBook Neo
- SSDs Not Safe Long-Term for Archives
- Spotlight Indexing Running Wild
- Excessive Mac SSD Wear
- Why I’m Usually Unnerved When Modern SSDs Die on Us
- Storing SSDs Without Power
- The SSD Endurance Experiment
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In addition to everything Howard wrote, I also think that when shopping for an SSD, one key data point that should be taken into consideration, in addition to size and performance specs, is the drive's longevity.
Expressed as "TBW" (TeraBytes Written), it is an approximation of how much writing the manufacturer expects the device to be able to handle before you need to start being concerned about reaching the end of the device's life.
Larger SSDs, of course, have a larger TBW, because they have more physicial storage, but different models with the same capacity can have different longevities on their spec sheets - sometimes as much as a 4:1 difference between the longest and shortest anticipated lifespan.
For myself, when I build my SSDs (mating an NVMe stick with a USB enclosure), I seek out the drives with the highest longevity, even if those models might not have the highest performance or the lowest price.
I realize that some people disagree with me, claiming that published longevity doesn't actually mean anything. Much like how many people believe other published reliability statistics like MTBF are equally meaningless. If this is your opinion, I am not trying to change your mind. But perhaps this information may be useful to others.
I remember in the early days of SSDs on Windows especially, overprovisioning was a big thing. I remember the advice being to leave as much as 20% of the drive unallocated. I wonder if Apple does anything like this, especially on the MacBook Neo base configuration which seems doomed to this exact problem.
And all of Apple’s laptops with Apple silicon have proprietary, non replaceable storage. That makes them a non-starter for me. Generic PCs with Linux seems like the natural path to take, especially given macos Tahoe.
I’ve not come across a user of a Mac with an SSD claiming that the drive is now unusable. Has anyone else?
I imagine local time machine snapshots filling the disk until there is only like 5gb free space..can’t be good
Time Machine's hourly local snapshots are only retained for 24 hours.
If you're writing a lot of data, then those snapshots could consume a lot of space. But most of the data in each snapshot will be identical to the other 23 (and the active file system), so the incremental storage consumed shouldn't be too bad.
But if they do start consuming too much space, you can delete them. And macOS is supposed to auto-delete the oldest ones in order to free up additional storage, should it be required.
