What are the trade-offs between a single-org and a multi-org strategy?

The case for a single org: one view of the customer, cross-business reporting without integration, reuse of configuration and process, one release calendar and one governance body, and lower licence and administration overhead per unit of function.

The case for multiple orgs: genuine process independence, regulatory or data residency separation, independent release cadences and autonomy, insulation from another unit's customisation risk, and relief from org-level limits and platform ceilings that a very large consolidated org can approach.

What decides it is usually the customer overlap. If the business units share customers and need to see them together, that is the strongest single argument for consolidation, and it is hard to replicate with integration. If they share no customers and operate under different regulators, most of the consolidation benefit disappears while all of the migration cost and governance conflict remains.

The trap I look out for is the mitigation that sounds cheap: "we will consolidate the data but keep the interfaces separate". That is achievable, but it converts an org strategy decision into a permanent sharing, profile and layout complexity that somebody maintains forever. I would rather price it honestly than let it be assumed away.