Non-disclosure agreements normally have a duration clause followed by a perpetuity clause, something like this,

9.1 This Agreement shall commence on the date of signature by the party last signing or the of first disclosure date specified in Annexure A, whichever is the earlier, and shall endure for a period of 3 (three) years.

9.2 Notwithstanding the expiry or termination of this Agreement, the non-disclosure provisions set out in paragraph 4 shall endure in perpetuity or until such time as the Confidential Information is released into the public domain through means that do not amount to a breach of this Agreement by the Receiving Party.
I don't really understand the point of having the first clause if it is overridden by the second clause. Could anyone explain this to me?

In what cases does the first clause apply, and in what cases does the second clause apply? Does that mean that any information disclosed after three years is not governed by the agreement (i.e. a new one must be signed)?