I got my iPhone 15 on Jan 19, 2024. Right now it says:
-Battery Health says Normal
-Maximum Capacity is 91%
-Cycle Count is at 367
I charge it daily through the USB-C port, mostly charging it when it's at 40-50%, but sometimes it reaches 20% depending on what happens that day.
I will say that the last 2-3 months, which would be some 14-15 months after I bought it, the battery seems to have gotten noticeably worse and drains faster, and I'm not using it any differently than usual.