Do I really need to get a new battery?
I have a message in my settings saying that my battery needs to be replaced but it’s been working just fine.
iPhone XS Max
Question marked as
If it says it needs to be replaced, then in probably does. But you are not forced to.
What does it say for the Battery health percentage in Settings ➜ Battery ➜ Battery Health?
In general its recommended to replace it once its reaches 80% or lower. But there's nothing that says you absolutely have to change it if you don't want to.
Battery replacement for an iPhone Xs Max will be $89 USD.
click here ➜ iPhone Battery Repair & Replacement - Apple Support