As organizations race to adopt post-quantum cryptography (PQC), “crypto agility” is often positioned as the solution that will make future cryptographic transitions seamless. This blog challenges that assumption, arguing that while agility reduces technical coupling, it does not eliminate the operational complexity, risk, and disruption inherent in real-world upgrades. From protocol constraints to compliance hurdles, the next transition will still be far from plug-and-play. For CISOs, the takeaway is clear: PQC is essential - but not sufficient. A security-in-depth approach that combines PQC with Quantum Key Distribution (QKD) on critical links offers a more resilient path forward, reducing reliance on future high-risk migrations and strengthening long-term protection against evolving threats