For me at my table, for ability checks it usually comes down to whether the check is to gain information. If it is, and the amount of information will be based upon the roll, I don't bother giving a DC because they will get what they get when they make the check. If they don't know something, there's no reason for them to know "how far off they were" from knowing something.
If you don't see the goblins hiding in the bushes, there's no reason for you to know how close you were to have seen them even though you didn't. That is unknowable information.
However, if there is an obvious failure state on a failed check, then yes I will give the DC. If you are making a check to leap off of a rock and down upon a target 15 feet below you... you will know whether or not you succeeded when you land-- you either hit the target or you didn't. So there's no reason for me to hide the DC in that case.
If you don't see the goblins hiding in the bushes, there's no reason for you to know how close you were to have seen them even though you didn't. That is unknowable information.
However, if there is an obvious failure state on a failed check, then yes I will give the DC. If you are making a check to leap off of a rock and down upon a target 15 feet below you... you will know whether or not you succeeded when you land-- you either hit the target or you didn't. So there's no reason for me to hide the DC in that case.
