New Delhi, Dec. 26 -- Spend a few minutes watching how people use their phones and you'll notice patterns that appear harmless but in fact might be harming the health of their smartphones - someone tops up from 92 to 100% before leaving home. Another stays plugged in at their desk all afternoon. A third runs navigation, music, and calls in the sun, screen at full brightness, the phone slowly heating up. None of this feels reckless. It's simply how phones fit into daily life now. The problem is that phones remember these patterns even when we don't.

Battery wear rarely comes from dramatic mistakes. It builds quietly through routine. Modern phones manage charging far better than they once did, but heat still does most of the damage. Leavin...