Storage full, and the largest file is something called Other

The points below about device storage bloat are ordered by how much difference they make, not by how often they get repeated.

Other is not a category, it is everything uncategorised

Storage summaries group files into recognisable types and put everything they cannot classify into a residual bucket with an unhelpful name. That bucket contains application caches, system logs, update files, message attachments, offline maps and partially downloaded media.

None of it is mysterious to the operating system, and the interface simply has no useful way to present several thousand small unrelated files. The practical consequence is that the largest apparent consumer of space is the one you are given no controls for. Per-app storage breakdowns, where the platform provides them, are far more useful than the summary chart and are usually one screen further in.

Caches come back because they are supposed to

A cache stores something expensive to fetch or compute so it does not have to be fetched or computed again, which is a genuine performance feature. Deleting a cache frees space immediately and slows the app until the cache rebuilds, at which point the space is consumed again. This is why cleaning utilities show impressive numbers and why the effect is temporary, which is not a scandal so much as a misunderstanding.

Three clicks later, most operating systems evict caches automatically when space runs low, so manual clearing mainly moves the timing. The exception is a genuinely misbehaving app whose cache grows without bound, and that one is worth finding and reinstalling.

Photos are usually the real answer

Camera resolution has risen faster than storage on entry-level devices, and video is the single largest consumer on most phones. Cloud photo services keep full-resolution local copies by default on many configurations, so the cloud copy adds convenience rather than space. Enabling optimised or space-saving storage keeps small local versions and downloads the original on demand, which frees a great deal at once.

Duplicates from editing, screenshots, downloaded copies of things you already have, and messaging apps saving every received image all compound it. Reviewing the largest videos and the oldest screenshots takes ten minutes and typically recovers more than every cleaning tool combined.

Messaging apps quietly hoard everything

Group chats save received media locally by default in many apps, so a photograph shared with forty people exists forty times on forty devices. Long-running chats accumulate years of this, and the app's own storage screen usually offers a sort-by-size view that most users never open.

Automatic saving to the camera roll doubles it again, since the same file then exists in the app and in the photo library. Turning off automatic media download for groups is the single most effective setting change on a phone that is constantly full. It also stops the phone downloading video on mobile data, which is a second and separate benefit.

Why a full drive gets slow

Flash storage needs free blocks for wear levelling and for the fast write mode most controllers use, and both degrade as capacity fills. Performance therefore falls noticeably in the last portion of a drive, independent of anything the operating system is doing.

Read the terms and there it is: system updates also require free space to stage and apply, which is why a full device eventually stops updating and quietly becomes less secure. Keeping a meaningful margin free is worth more than the space itself, and the usual guidance is to stay below roughly eighty per cent. That margin is the cheapest performance improvement available on any device more than a couple of years old.

A cleanup that actually lasts

Start with the per-app storage list sorted by size, since one or two applications almost always account for the majority. Offload rather than delete apps where the platform supports it, as this removes the binary and keeps the documents and settings.

Turn off automatic media saving in messaging apps and enable optimised storage for photos, which addresses the recurring cause rather than the symptom. Delete the downloads folder, which on most devices is an archive of files opened once and never considered again. Skip the cleaning utilities, because the operating system already evicts caches under pressure and the tools mostly reclaim space that was never lost.

Everything above, in order of what to do first

1. Other is not a category, it is everything uncategorised. Storage summaries group files into recognisable types and put everything they cannot classify into a residual bucket with an unhelpful name.
2. Caches come back because they are supposed to. A cache stores something expensive to fetch or compute so it does not have to be fetched or computed again, which is a genuine performance feature.
3. Photos are usually the real answer. Camera resolution has risen faster than storage on entry-level devices, and video is the single largest consumer on most phones.
4. Messaging apps quietly hoard everything. Group chats save received media locally by default in many apps, so a photograph shared with forty people exists forty times on forty devices.
5. Why a full drive gets slow. Flash storage needs free blocks for wear levelling and for the fast write mode most controllers use, and both degrade as capacity fills.
6. A cleanup that actually lasts. Start with the per-app storage list sorted by size, since one or two applications almost always account for the majority.

The takeaway

Turn off automatic media saving, then go and look at your videos.

The fix is usually trivial, which is the most annoying part.