The warning always shows up at the worst moment. You’re about to film something that matters, or install the app a restaurant insists you need to order, and the phone tells you there’s no space left. So you start deleting photos in a panic, one by one, and free up about 40 MB.
There’s a better order to do this in. Photos are rarely the first thing to go after, and the biggest wins usually sit in places most people never open. This guide works through them from the largest and easiest to the smallest and fiddliest, for both iPhone and Android.
If you read Polish, or don’t mind leaning on your browser’s translate button, Filesonic.pl has a technology section full of short how-tos in the same spirit, covering things like removing a card from Apple Pay or locking down who sees your Facebook friends list. Worth a bookmark if you’re the person family members call when their phone misbehaves.
Start by looking, not deleting
Before you touch anything, find out where the space went. On an iPhone, open Settings, then General, then iPhone Storage. On Android, open Settings and look for Storage (Samsung puts it under Battery and device care). Both show a bar split by category and, below it, a list of apps sorted by how much they take up.
Give it a few seconds to calculate. The answer is often surprising. A messaging app at 12 GB. A podcast app holding every episode you’ve ever downloaded. A “System data” or “Other” slice that seems to grow on its own.
Messaging apps: usually the biggest single culprit
WhatsApp, Messenger, Telegram and the phone’s own Messages app quietly store every photo, video, voice note and meme anyone has ever sent you. Group chats are the worst. One active family group can pile up gigabytes over a couple of years.
In WhatsApp, go to Settings, then Storage and data, then Manage storage. You get a list of chats sorted by size and a separate view of large files and files forwarded many times. Sort by size, delete the videos you’ll never watch again, and keep the text of the conversations intact.
On an iPhone, Settings, then Messages, then Keep Messages lets you change “Forever” to one year or 30 days. Be careful, because this deletes old conversations entirely, not only the attachments. The gentler route is to open iPhone Storage, tap Messages and use “Review Large Attachments” to delete just the heavy files.
Offline downloads you forgot about
Spotify playlists downloaded for a flight two years ago. Netflix episodes you finished. Podcast episodes that auto-download and never get removed. Google Maps offline areas for a city you visited once.
Open each streaming app and look for a Downloads section. This is usually where the second big chunk of space hides, and deleting it costs nothing, because you can download the same content again whenever you like.
Photos and videos, done properly
Now photos, but not one at a time.
Video eats space much faster than photos. On a recent iPhone, a minute of 4K video at 60 frames per second takes roughly 400 MB according to Apple’s own camera settings screen. If you film your kids’ school concert in 4K, that’s gigabytes per event. For everyday clips, dropping to 1080p in the camera settings saves a lot and rarely makes a visible difference on a phone screen.
If you use iCloud Photos, turn on “Optimize iPhone Storage” in Settings, then Photos. Full-resolution originals stay in the cloud and the phone keeps smaller versions, downloading the full file when you open it. On Android, Google Photos has a “Free up space” option that removes device copies of anything already backed up.
One trap catches almost everyone. Deleted photos don’t disappear immediately. They go to “Recently Deleted” on iPhone or the Trash in Google Photos, and they stay there for 30 days or more, still taking up space. If you’ve just deleted a pile of videos and the storage bar hasn’t moved, that’s why. Empty the bin.
Apps you don’t use
iPhone has a setting called “Offload Unused Apps” at the top of the iPhone Storage screen. It removes the app itself but keeps your data and documents, so if you reinstall it later, you pick up where you left off. You can also offload apps one by one from the same list.
On Android, the free Files by Google app shows apps you haven’t opened in weeks, along with duplicates and oversized files. It’s the most useful cleaner on Android, largely because it doesn’t try to sell you anything.
What you can skip
Cleaner apps from the app store that promise to “boost” your phone. Most of them clear caches the system already manages on its own and fill the rest of the screen with ads. Some ask for permissions no storage tool needs, which is a worse sign.
Clearing every app’s cache on a schedule. Cache is temporary data that makes apps load faster. Clear it and the app rebuilds it within days, so you get a slower phone for a week and the same storage use by the end of the month. It’s worth clearing for one specific app that has ballooned to several gigabytes, not as a routine.
Factory resetting to fix storage. It works, briefly, and costs you an afternoon of setting everything up again. If “System data” is huge on an iPhone, a simple restart sometimes shrinks it, because part of it is temporary files the system clears on reboot.
Keeping it from filling up again
Two settings do most of the work. Turn off auto-download of media in WhatsApp (Settings, Storage and data, Media auto-download) so videos from group chats only land on your phone when you tap them. And set your podcast app to remove episodes after you’ve played them.
After that, a quick look at the storage screen every couple of months is usually enough to catch whatever has started growing before the warning pops up again.
