Storage advice on the internet has a problem: it lists twenty tips of wildly different value as if they were equals. Clearing Safari's cache and deleting your videos both get one bullet point, but one frees 60 MB and the other frees 6 GB.
Here's the honest ranking, by gigabytes recovered per minute of effort.
Tier 1: videos
Open Settings → General → iPhone Storage and look at the chart. For most people, Photos dominates, and within Photos, videos dominate. A minute of 4K footage is roughly 400 MB. That screen recording of a bug you reported in 2024 is still there, and it's the size of 100 photos.
Review your longest videos first. Ten decisions can free more space than an hour of photo triage. This is exactly why Sweep has a dedicated "Longest videos" pile: biggest wins, fewest swipes.
Tier 2: Messages attachments
Every photo someone ever texted you is stored twice: once in their thread, once if you saved it. Go to Settings → General → iPhone Storage → Messages and iOS will show you the biggest attachments, sorted. Group chats that ran for years hide gigabytes.
Tier 3: the photo library itself
Thousands of screenshots, burst duplicates, and blurry shots. Individually tiny, collectively huge. The Photos app is a poor tool for this review; a swipe-based cleaner does it in minutes a day.
Whatever tool you use, remember the step everyone forgets: deleted photos sit in Recently Deleted for 30 days, still occupying space, until you empty that album.
Tier 4: apps you don't use
Settings → General → iPhone Storage lists apps by size with their last-used date. Offload or delete the ones you haven't opened this year. Games are the usual suspects: a couple of forgotten titles can hold 5 GB.
What barely works
- Clearing Safari cache: usually well under 500 MB.
- Deleting emails: Mail stores very little locally.
- Restarting your phone: clears temp files worth a few hundred MB at best, and they come back.
- "Storage cleaner" apps that promise one-tap miracles: iOS doesn't let any app delete system junk. Anything promising that is selling placebo. A cleaner can only help you review your own media faster, which, to be fair, is where the gigabytes are.