People think that they should charge their Galaxy Note 3 for 16 hours before first use. The truth is that with modern battery technology, you don’t need to do this. Don’t overcharge your Galaxy Note 3. Just charge it to full and you will be fine.
That full charge and deplete that you hear about on first use is for older battery technology, not newer battery technology.
That advice refers to nickel hybrid and cadmium batteries which haven’t been used in phones for 10 years now.
Below is a picture of my Samsung S5 series laptop which shows an option in the bios to limit battery charge up to 80%, as charging over 80% frequently is not good for your battery life in the long run. After first full charge, you should just consider charging your phone up to 80% every time to extend your battery life so you don’t end up buying a new battery too soon.