If you let the battery on any phone drop down near 0 before charging it, you'll start having problems with the battery in a month or two. On the other hand, if you charge it when it drops to 50% (or turn it off if it gets to 40$ and you still can't charge it) ... I had to replace my Note 3 battery after 4 years because it started bulging (a manufacturing defect), but at almost 7 years old, it's still running at about 98% of what it was when it was new. (It's never been discharged lower than 45%. It's just dangerous to leave a battery like that in the phone unless it's lying face down with the back cover off - in case the battery decides to pop.) My Pixel 2 battery, coming up on 2 years old, is still showing 100% efficiency.
But drop the battery down to 0% every time, and you'll have to replace it every month.
It's treatment, not the S9.