Charging and Discharging tips for Li Polymer battery of phone?

[AC Question]

Hi, I have redmi note 4 which have LiPo battery; can you help me with following query: For long life of my battery, how shall I charge and discharge battery? I usually charge up to 90% and discharge upto 20%, shall I do it 0 to 100%. Thanking you in anticipation. With best regards, Rakesh Dhedhi