In which situation does the doctrine of dependent revocation typically come into play?

The doctrine of dependent revocation is specifically applicable in cases where a testator revokes a will based on the belief that a subsequent will or other disposition is valid. When a testator creates a new will or makes a new disposition while thinking that it effectively replaces or revokes the previous one, but the new will or disposition is later found to be invalid, the doctrine of dependent revocation allows the earlier will to be revived.

In this context, it recognizes that the testator's intention was to revoke the first will based on a mistaken belief in the validity of the second. If the second disposition is effectively invalid for some reason (such as lacking proper formalities), the earlier document will be reinstated as if the revocation had not occurred, thus fulfilling the testator's original intentions.

The other contexts do not invoke the doctrine in the same way. For instance, when a will is lost and presumed revoked, it doesn't relate to the testator's intention regarding a new will or disposition. In the case of multiple original wills, unless one specifically revokes another with clear intent, the doctrine isn’t directly relevant. Finally, when a beneficiary contests the will, it does not directly involve the issue of revocation based on a mistaken belief