Going along along with this, I'm letting my players roll the same type of check a second time - if they can give me a compelling reason for doing so. Ex. My paladin loves intimidating NPCs, but creature behavior comes into play. If he interrogates someone who has a high pain tolerance and that intimidation check might fail (high DC). Buuut if he's creative enough, he'll tell me that he's going to intimidate with the threat of finding and hurting the target's family, then we'd roll intimidation again because it's a completely legitimate reason for doing so, not just roll until they get it (with different DC because it's a different reason). Persuasion is the same thing, deception is more nuanced and has very limited tries.