Every lithium-ion battery degrades a little with each charge cycle — that's not a defect, it's chemistry. The question isn't whether your battery will wear down, it's how to tell when it's worn down enough that replacing it makes more sense than living with it.
Signs your battery needs attention
Rapid, unpredictable drain
Your phone drops from 80% to 20% in a couple of hours of normal use, even with no heavy apps running.
Random shutdowns
The device powers off suddenly at 20–30% battery, especially in cold weather or during intensive tasks.
Swelling
A back panel that's started to bulge or a screen lifting slightly at the edges is a battery safety issue — stop using it and get it checked immediately.
Battery health below 80%
Both iPhone (Settings → Battery → Battery Health) and most Android phones show a battery health percentage — once it dips under 80%, capacity loss becomes noticeable.
How to check battery health yourself
- iPhone: Settings → Battery → Battery Health & Charging, which shows "Maximum Capacity" as a percentage of the original.
- Android: Dial
*#*#4636#*#*on many devices, or check Settings → Battery → Battery usage for charge cycle estimates; some manufacturers (Samsung, OnePlus) include a dedicated battery health screen.
Rule of thumb: most phone batteries are rated for 500–800 full charge cycles before falling to around 80% of original capacity. For a phone charged daily, that's roughly 1.5–2.5 years of typical use.
Genuine parts vs. cheaper alternatives
Not all replacement batteries are made equal. A genuine or OEM-grade cell is built with the safety circuitry and capacity rating your phone expects; unbranded cells sold purely on price can undercharge, overheat, or wear out again within months. At Rephox, every battery replacement uses parts we'd be comfortable putting in our own phones, and it's backed by the same 6-month warranty as every other repair.
If your device is having trouble for reasons beyond the battery — freezing, restarting on its own, or not charging at all — it's worth ruling out the charging port or software first. Our device diagnostic checklist covers the basics before you book a repair.