D&D 5E How do you set DCs?

[cbwjm]

I also use enemy skills and abilities to set DCs, the most common is sneaking against the enemy passive perception, but just the other night the players rolled perception against a DC 17 to spot some shadow demons. I sometimes do the same for interaction checks rather than making an opposed roll, I just add 10 to the NPC's Insight or perhaps their own interaction skill. I find that's a good way to set DCs when the players are in interacting with the people of the setting.

 

[aco175]

I sometimes call for group checks and the party needs half the PCs to make it or all fail. This tends to be something like a group check to cross a slick, rickety, bridge not in combat, or maybe all the party sneaking up to the entrance of the castle without being seen. Since it would be likely a fighter fails with his armor penalty and Dex, I have a group check with the rogue helping the fighter shown in the 50% of the PCs need to make the check.

I also sometimes have checkes where the standard may be 15 and to do something fast may be a 20. A slippery floor may be a 15, but the rogue wants to move full speed, so the check is 20, sometimes it could be with disadvantage but that tends to be worse then the +5 to the check somehow, even though the mast says a 5 penalty.