I tried very hard to keep my battery healthy by only charging my phone to 80%, which resulted in me running out of battery quite often throughout the day, interrupted charging cycles etc., which apparently all were worse than just charging to full (via "optimized charging" which finishes the charge in the later hours) overnight.

I lost about 10% of reported battery health that way in less than a year, switched to just charging overnight or whenever getting close to empty, and have lost all of 3% over the second year of using this phone.

On top of that, swapping an iPhone battery is annoying, but having to worry about all of those battery health concerns is much more tedious.