Consider explaining the need for ablution before prayer. A beginner may need the basic steps and qualifications explained. A scholar familiar with the subject may need only clarification of the specific legal point under discussion.
For a beginner: explain the relevant basics plainly enough to prevent misunderstanding.
For a specialist: focus on the precise contested or exceptional point and omit already shared preliminaries.
The underlying subject has not changed. What changes is the amount and form of explanation appropriate to the addressee.