“6 hours remaining” on a brand-new iPhone 18 is a library problem wearing a wifi costume. Real numbers below.
The quick answer
Budget 10-20 min per 50GB on solid wifi via Quick Start. A cleaned ~60GB library transfers during unboxing; a 250GB meme-and-4K archive takes an evening. Biggest lever isn’t cables — it’s gigabytes: delete the giants first (transfer-stuck guide), then migrate to your Duo or 18.
Realistic times
| Library | Quick Start (good wifi) | iCloud restore |
|---|---|---|
| 50GB cleaned | ~15 min | ~30-60 min |
| 128GB average | ~45 min | 1-3h |
| 256GB bloated | 2-4h | Half a day, maybe |
What the table gives you: permission to clean first — an hour of triage saves three hours of staring. What it does not give you: guarantees. Launch-day Apple servers and hotel wifi break all math.
The 30-minute pre-transfer
- Biggest-first video kill (10 min): 4K guide.
- Bursts + screenshots (15 min): duplicates, screenshots.
- Empty Recently Deleted (30 sec), back up irreplaceables, Quick Start on power + stable wifi.
The bottom line
Transfers copy everything, including 2023’s junk. Clean the old phone, the new one — 18 or Duo — starts fast and stays fast.