And now that you've read that. Read this:
Which is the reality of the situation.
Your camera and charger are managing your battery so that you don't run into a full discharge. Unless you run it down and then leave it sitting discharged for a month you'll never have an issue.
You can read what the manufacturer learned in testing, but that was raw cells, not the battery in your camera.
Do what you want, I don't mind !
My batteries last many times longer than my friend ones who don't care about.
The integrated circuitry in the battery and the charger prevent for deep discharge and overcharge, but don't care about longevity.
If you want your batteries last longer, don't let them discharge too much.
Charging to 80% is difficult, because the charger does not indicate accurately real charge.
So if you use it immediately after charging, you may charge the battery to full charge.
But if the battery has to stay for months without use, you have to check the voltage.
Store them at about 3.7 to 3.8V/cell.
Many manufacturers give that advice.