AWS popularized the "6 Rs" framework for application modernization, and it has become standard vocabulary for cloud migration and application modernization planning. Like many frameworks, it's better at structuring thinking than providing definitive answers — applying it well requires judgment, not just pattern matching.
Retire: The Most Overlooked Option
A surprising percentage of enterprise application portfolios consists of applications that are barely used, duplicated by other systems, or no longer aligned to business needs. Decommissioning these applications reduces maintenance burden, security risk, and licensing costs — with no corresponding loss of business value. Retirement should always be the first question asked about any application.
Rehost: Fast but Limited
Lift-and-shift (rehosting) moves applications to the cloud without modification. It's fast, low-risk, and achieves infrastructure cost savings. But it captures none of the cloud-native benefits — the application remains architecturally unchanged, with the same scalability constraints and operational model. Rehosting should be a tactical move (buy time, exit data center contracts) not a long-term strategy.