I upgrade based on how much storage I use. Bare minimum 2TB. If I want to use computer for 3-5 years, the internal storage capacity would have to be 8TB or higher, which both I can’t afford and doesnt exist (more than 8TB). It is incredible to think I am running out of storage at an alarming rate without doing any sorts of video editing.
Reason? I staunchly against the idea of storing everything in the cloud. My data MUST BE stored locally and I manage it. I do use cloud storage but not in a manner that I completely neglect local storage. In fact, my current MBP having no local mirrored copy of my iCloud photos library and OneDrive files worries me quite a bit.
Regarding storage, I still have doubts honestly. I find it a bit difficult to calculate it not only because of how much storage I want to leave free to improve performance (surprisingly I’ve been using my M2 iPad Pro for more than 6 months with the storage almost full, with just a few GB free, and it was still very snappy; I guess it’s something of Apple Silicon and having 8GB of RAM for iPadOS) but also because of the SSD degradation. Theoretically, lifespan doubles when you double the storage capacity, so having double the capacity means it can take more TBW than smaller SSDs.
On my 128GB iPad Pro the election of a bigger SSD is clear because I end up filling the 128GB and the 256GB will be faster and provide a longer lifespan (although when I exchange it to replace the battery, I guess the SSD will be new). If I manage to sell this M2 iPad Pro this holidays I’ll probably grab a 256GB one.
However, on the Mac side, I don’t have it clear at all. Keep in mind I don’t use cloud storage either. Unfortunately, SSDs are not replaceable on Mac mini or MacBook Airs… and the SSD has a lot more work on macOS, swapping and such. It will degrade faster, it is not replaceable, and that would lead me to get a bigger SSD if I plan to keep the Mac for 8 to 10 years. I have a replaceable Samsung EVO SATA 1TB SSD (it was dirt cheap) on my old 2014 Mac mini, and I usually only fill around 250 to 300GB, if we take into account that sometimes I work on video files or download content that takes 3 or 4GB per file. But I copy them on external drives, and I format and reinstall my Mac from scratch at least once per year, usually in spring or summer. That way, I never use a ton of storage on my Mac.
But still, despite this, I am considering for my next Mac, which will be an Apple Silicon Mac, at least 1TB. For a longer lifespan on a device which I won’t be able to replace the SSD from it once it gets to the end of life. If some upcoming macOS version gets released with a new memory leak, or other memory management glitch (like it was the case with Big Sur or Monterey) the SSD TBW can skyrocket and I would be killing my SSD, which again, isn’t replaceable on many macs. Or if I download or move big files, or let’s say I try learning video editing or something similar, I would be using many TBW, and if I can double them by doubling the storage, why settle on 512GB which, probably, would be enough?
Those are my worries and reasoning regarding SSD, in relation to the long time I plan to keep my next Mac. An M4 Mac, probably.