How would you decide between agile, waterfall and a hybrid approach for a Salesforce programme?

I decide from constraints rather than preference, and I say so out loud, because the answer that impresses is the one that names the trade-off.

The drivers that push towards iterative delivery are requirements that will change as users see working software, a business that can give the team regular attention, and value that can be released incrementally. The drivers that push towards a formal, gated approach are externally fixed scope, a regulator or auditor who needs traceability from an approved requirement to a delivered component, fixed-price contracting, and dependencies on other programmes with immovable dates.

Most large Salesforce programmes end up hybrid: the scope is baselined and approved once, the build and test happen iteratively inside that baseline, and changes to the baseline go through change control. I would rather say that plainly than pretend a regulated insurer can run pure Scrum.

I also raise team maturity, because it is the constraint people skip. A team with no source control, no automated tests and no product owner will not succeed with two-week sprints, whatever the contract says.