DMG - DC by level table look wonky?

[Mr. Greengoat]

I was reading through the DMG about the DCs by level (p.42) and I was having a hard time trying to understand the logic behind the progression on the table in comparison to their rule of thumb of DC = 10/15/20 + half character level.

It seems the Rule of thumb and the table don't line up very well.

Also I have a hard time thinking of situational DCs (which should seem static) as relative to character level. For example the DC to keep from slipping on Cave Slime (p.67) has increased with the character level so if a third level PC and a 11 level PC are on the same patch of slime they would both have to roll against different DCs or they would have the same DC that would either be too hard to too easy. (Do we have level 11 cave slime? or the less slippery level three cave slime?)

I understand the mechanical reasons for the adjusting DCs but it somehow feels counter-intuitive to come up with new DCs for the same situations as the party gains levels.

 

[James McMurray]

The DCs and the rule of thumb don't line up because the rule of thumb is meant to let you get a less accurate but quicker DC by memory.

DCs for challenges shouldn't change. It's the challenge that changes to match the DC. A 5th level party finds DC x cave slime. A 15th level party finds DC x cave slime on a slope that adds y and in a room that's quaking just enough to add z. At least, that's my take on it.

 

[Ridley's Cohort]

An experienced gamemaster gave me this useful pearl of wisdom: "Learn when not to pick up the dice."

The level 11 party meets level 11 Cave Slime -- that is a memorable encounter for which the DC rule of thumb is useful.

Level 11 parties do meet level 3 Cave Slime, but that is not something normally considered worth resolving with encounter mechanics or the usual skill mechanics. Just roleplay that out as a mood-enhancing device, and leave the dice on the table.

A scenario where a level 11 PC and a level 3 PC would meet the same Cave Slime is considered an extreme outlier, for which of usually useful rules of thumb will fail. (Obviously such things can easily happen to NPCs, but the DM does not need to roll dice for that either.)