A migration checklist that survives contact with the estate
The order matters more than the tooling. Inventory, then govern, then validate, then move — and only what has a case for moving.
Inventory before you estimate
Scope set before the inventory exists is the single most common reason these programmes overrun. Get the asset count, the dependency graph and the feature distribution first, even if it delays the business case by a fortnight.
Put the estate under management while it is still on AEM
Identity, revisions, validation and release management are worth having whether or not you migrate. Doing them first means the migration is a change to one managed system rather than a leap between two unmanaged ones.
Add validation to CI before you convert
If a conversion breaks something, you want the failure attributed to the conversion. That only works if the estate was already green.
Convert in waves, verified per wave
Order waves by risk, not by folder. Each wave proves its output matches the agreed definition of equivalence before anything is cut over.
Be willing to stop
Some forms should stay where they are, and some estates should not migrate at all. A plan that has no stopping condition is not a plan.