128, 256 or 512 GB: How Much Storage You Actually Need

The one choice you cannot revisit

Almost everything about a phone can be changed later. You replace a battery, you replace a screen, you buy a case to go with it. Storage, no: the memory chips are fixed to the board and are not a part you have added in a shop. Anyone who buys too tight is stuck with it for the whole life of the device, or has to organise the rest of their belongings around their full phone.

That is why this is the one specification where you are best off going a step roomier than you think you need.

Where the space actually goes

The system itself already takes a bite of around ten gigabytes, depending on the version of iOS. What is left after that disappears, for almost everyone, into the same four buckets: photos and video, apps with their own data, messages with all the attachments that sit there for years, and downloaded music, series or maps for offline use.

Of those four, the messages bucket is the quiet thief. Five years of conversation history with photos and videos of family runs up to several gigabytes without you seeing it happen.

Figures to work with

• An ordinary photo from the main camera: a few megabytes. A thousand photos therefore stay in the order of a couple of gigabytes.
• A photo in the unprocessed format of the Pro models: a multiple of that, up to several tens of megabytes per shot.
• Video in 1080p at thirty frames per second: roughly sixty-five megabytes per minute.
• Video in 4K at thirty frames per second: about one hundred and ninety megabytes per minute. Half an hour of holiday footage is therefore already several gigabytes.
• The professional recording formats on the Pro models: several gigabytes per minute. Anyone working with those already knows that one hundred and twenty-eight gigabytes is not enough.
• Large games: from a couple of gigabytes to well over ten each.
• A season of a series offline: a couple of gigabytes, more in high quality.

With those numbers you can work out your own year. If you film two hours in 4K a year, that alone is more than twenty gigabytes that will never go away again.

Look at your current device first

The most reliable prediction is in your own pocket. Go to Settings > General > iPhone Storage. There you can see what you are using now and on what. Do not look only at the total but also at the split: someone with twenty gigabytes of apps and a hundred gigabytes of photos has a different problem from someone with the reverse.

Then take your current usage and add half again for the years to come. If you are on ninety gigabytes now, one hundred and twenty-eight is too tight for a device you want to use for another four years. Photos and messages grow; they never shrink.

Why iCloud does not solve this

iCloud is a good backup and a good way to have your library everywhere, but it is not a substitute for storage. You get five gigabytes free, which is often already too little for a single backup of a modern phone; more means a paid subscription.

If you switch on the option in Photos that optimises space, your device keeps smaller versions and the originals stay in the cloud. That works, but it also means that you cannot get at your originals without a network, that exporting an old video means waiting, and that on a good connection your device still fills up with versions it finds convenient to keep.

In other words: iCloud softens a tight phone, but you notice every day that it is tight.

When which size fits

One hundred and twenty-eight gigabytes

Enough if you mainly call, send messages, navigate, do your banking and take the occasional photo, and if you regularly let your photos drain off to a computer or to the cloud. Also a fine size for a second device, a work phone or a first phone for a child. Tight as soon as you start filming in 4K or like to take series along on a trip.

Two hundred and fifty-six gigabytes

For most people this is the size you stop thinking about for years. A family library of photos, years of messages, a pile of apps and the occasional video: that fits. It is also the size that is easiest to place when you sell it on, because it is what most buyers are looking for.

Five hundred and twelve gigabytes

Needed if you film a lot in 4K or in the professional formats, if you want your whole music or film library offline, if you are into large games, or if you refuse on principle to delete anything and want to keep the device for six years. If you recognise none of those four, you are paying for space that will stay empty.

What a full phone does to you

A device that is permanently up against its ceiling does more than just show messages. It can no longer install an iOS update, because that needs temporary free space. It stops filming at the worst possible moment. And you are constantly busy clearing up instead of using it. Count on keeping at least ten per cent of the storage free as working space.

The rule of thumb

Look at what you use now, add half again, and then choose the first size that comes out above that. If you are hesitating between two sizes, take the larger one: the difference in purchase price is smaller than what it costs you to live with a full phone for four years, and when you sell it on you get part of that difference back, precisely because large storage is scarce second-hand.

Which storage sizes are available per model can be seen with the iPhones. For anyone who mainly watches videos and reads, a device with small storage alongside an iPad is often a better split than cramming everything into one device.