How would you decide between choreography and orchestration for a new multi-service business process?

The main factors are step count, coupling tolerance, and how much an explicit audit trail matters. For a short process — two or three loosely related steps — choreography is usually the simpler choice: it keeps participating services decoupled from each other and avoids introducing an extra orchestrating component for a plan that's still easy to hold in your head. Once a process grows past roughly four or five steps, involves multiple distinct failure paths each needing its own compensation, or needs to be clearly auditable end to end, orchestration becomes the better fit, since it makes the entire sequence and its failure handling visible in one component, in exchange for that orchestrator being explicitly coupled to every participant it coordinates. A common, pragmatic pattern in real teams is to start new processes with choreography and deliberately migrate to orchestration once the implicit plan starts becoming genuinely hard to trace.