Lithium batteries

depth of discharge dod should not be more for longer life as it will reduce no of cycles it lasts. . so it is advised  to charge the battery before it discharges completely and to charge more often between uses.

in experiment LiPO4 battery showed 15000, 900,600 life cycles with 10% , 80%, 100% DOD respectively. 

lab report suggests not to charge 100% even but charging up to 90% gives better life. 

battery capacity reduces to 65% at temperatures above 40 degrees after 1 year.

charging to peak voltage reduces life. 

https://batteryuniversity.com/article/bu-808-how-to-prolong-lithium-based-batteries

charging the pack to only 80% instead of a full charge, and discharging to 30% is good for long life

https://batteryuniversity.com/article/why-mobile-phone-batteries-do-not-last-as-long-as-an-ev-battery

ultra fast charging will stress battery and must be used only up to 50% of the battery.

https://batteryuniversity.com/article/bu-401a-fast-and-ultra-fast-chargers