Common warning signs

• Battery life is noticeably shorter.
• The iPhone shuts down unexpectedly.
• Performance drops under load.
• A message says battery health is significantly degraded.
• The display or enclosure begins to separate.

How to check battery health

In Settings → Battery you can review health, maximum capacity, and performance messages. Compatible models also provide cycle and charging-limit information.

80% is a reference, not a diagnosis by itself

Apple describes batteries as consumable components. Capacity near or below 80%, together with poor runtime or performance issues, is a good reason to request an evaluation.

When to stop using the device

If you notice swelling, unusual heat, odor, or display separation, turn the iPhone off and do not charge it. Never press, puncture, or manipulate a damaged battery.