iPhone 15 battery health rapidly declining: Is this normal?

Hello everyone,

I got my iPhone 15 mid-October 2025 second hand with its battery health at 98% (first use September 2024). I have noticed that the battery health is declining rapidly. I acknowledge that at first I was using the phone very heavily, as of now I have limited my use but still the battery health is dropping.

I try to practice some good charging habits eg keep Optimised Charging on, not letting it drop below 20% or charge over 80%. (Also I have updated to iOS 26.2 and I haven’t had any problems with the battery)

Right now my battery health sits at 92% with 233 cycles. Is this decline normal or is there any potential problem I should pay attention to?