Organizations typically employ six common strategies for migrating applications to the cloud: rehosting, repurchasing, refactoring/re-architecting, retaining, retiring, and reimagining. Rehosting, often seen in legacy migrations, can lead to significant cost savings, as demonstrated by GE Oil & Gas, which saved approximately 30% by rehosting applications without optimizations.

During the Portfolio Discovery and Planning phase, organizations should assess their existing environment, identify application interdependencies, and determine the complexity of each application. This information helps in outlining a migration plan that can adapt as they progress through the migration process.

The complexity of migrating applications varies based on factors such as the application's architecture and existing licensing arrangements. For instance, a virtualized, service-oriented architecture is generally less complex to migrate compared to a monolithic mainframe, which can present significant challenges.