Card Renting Strategies

Hey, a question. Do you rent all the cards you get? I have about 30 cards and I put them all for rent a couple days ago and I'm getting about 1 DEC a day lol. How much are you getting from renting? When did you start renting? Also I'm wondering if I should just buy a few good cards and start renting them, I have 1500 DEC atm. I would need to rent them for over 200 days for them to pay themselves back. But also I would still have the card that I bought/rented, so it is like doubling the DEC after 200+ days. What do you think?