Renting cards will depend on the purpose of the player. I have observed that some are renting so they can earn more DEC. Some are renting to level up.
If you are renting a card to make more DEC, it's better to look at your ECR or capture rate. It is suggested that you rent when your ECR is at 100% to make the most out of your rented card. It gives you more DEC, hence, the faster the return of your investment.
Lastly, don't forget to eat and have rest. I know those who are renting will probably be playing long hours to get a decent profit.
Enjoy playing!
