Oh really? Have you even read
Battery University website? I highly recommend that you do and get a better understanding how lithium ion battery works. It's not like we are using the NiCd where you have to drain it every time. Lithium batteries does not have "Memory effect".
What you are doing actually does more harm than good. If you fully drain the battery every time, that actually is much worse and shortens your battery life.
Indeed it has the protection circuit but that only protects the lithium battery from being overcharged.
If you compared to someone who uses 40-50% and then charge vs. full drain each time. Guess who will have a better battery health? Definitely not yours, and someone who uses 40-50% of the battery each time will likely have better battery life than yours.
If you can provide as a link to your source where a full drain each time is better then please educate us.