Insight doesn't fit in D&D's pass/fail skill system. Discussing how to run it at your table while keeping the whole party engaged.
As a matter of adventure design (or when improvising as a DM), you shouldn't lock mission-critical information behind a skill check. Because if the characters fail the check, the plot line is dead. But, the solution isn't to get rid of skill checks. The solution is progressive skill checks, starting at 0.
Why have 18 skills when you can have FIVE?
We’re giving D&D players more agency over the narrative implementation of their skillsets by streamlining a bloated system and highlighting a popular variant rule.
Scaling up Difficulty Class (DC) on successive checks is a bad idea. Some DMs like to increase DCs on successive attempts, dissatisfied with the relative ease of a standard skill check (or saving throw). However, doing this has drawbacks which you can see in action on the DC Increase Chart.