
Hi all, I am Vinsant, this is my 1st post here. I start playing Splinterlands at mid of December 2021. I just hit my Diamond 1 rank yesterday.

As we all know, to increase the level, I need to have enough level and enough CP (card strength). This is no problem for ratings, because I will get it when I win the battle. I need to rent a card to increase my CP. Deciding to rent a card is an investment decision, because I need to know that the DEC that I invested in the rental card will eventually be returned to me after a battle. So I need to know how much DEC I will spend on renting and how much DEC I will win in each level of battle.
I tried to search a lot of articles about rewards for each rank level, but I couldn't find what I needed, so I decided to research and analyze the information by myself. I am very happy to share my results with everyone who likes this game.

As you can see, maintaining the Gold 2 level is the most inefficient. I don’t know why the DEC reward is designed this way. It seems to be good for new low-level players, good for old high-level players, but not good for intermediate players.
All in all, it's best to stay low or climb higher instead of going into the middle.
This may be a mistake in my findings. I hope to discuss for the purpose of learning. Any comments are welcome, thank you.