I spent a solid 3 months micromanaging my rental cards to optimize my daily earnings as much as possible. The max that I was ever earning was around 1.5k DEC a day.

I eventually gave up because it took too much time and effort to constantly stay up-tp-date with all of the changes in Splinterlands and how it effected the rental market.

Also, I would have "investment" cards which were the most in-demand cards to rent but when a new announcement came out or new cards would get released they would significantly tank in value, so you have to essentially always guess the next meta correctly otherwise all the DEC you earned by renting the card would be so insignificant compared to the value lost.

I remember that I had a Gold Foil Djinn Oshanus which was around $300 which I was renting out and getting decent DEC, especially during the EoS rental demand. The problem was that I didn't pay enough attention for a week or so and the price just dropped like crazy where I ended up losing much more in the value of the card than the amount of DEC I earned.

So, yeah, I gave up rentals completely which was a great decision for me 😂

!PIZZA