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Settings > Battery > Battery Health, what's the Maximum Capacity?

If it's much over 80% - probably the battery is "okay" and maybe some additional troubleshooting needed on battery life.

If much below that - probably time for a new battery or new iPhone.
 
Just because the battery is starting to die off does not make the phone bad. If you have been very happy with the phone then just get a new battery installed to restore the phone. I did this for my 15 Pro and it now has a battery health of 105% and lasts all day. I still daily use my 15 Pro because I have been pleased with this device.
 
Just because the battery is starting to die off does not make the phone bad. If you have been very happy with the phone then just get a new battery installed to restore the phone. I did this for my 15 Pro and it now has a battery health of 105% and lasts all day. I still daily use my 15 Pro because I have been pleased with this device.
My battery health is 88%
 
My battery health is 88%
That is still not bad. I discovered the battery installed in my pre-owned Blue Titanium 15 Pro (purchased from Amazon renewed) was a boosted battery so I ordered a new high capacity diagnostic compatible 3419mAh SUNWODA battery to install and performed the battery replacement service myself. I have all the tools necessary to perform Apple service level repairs on my own iPhones.

For reference my second Blue Titanium 15 Pro purchased directly from Apple, has a 3366mAh SUNWODA battery providing that device with 103% battery health.

I wouldn't worry about needing a new battery on your iPhone until the battery health reaches 80% range.
 
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