Understand what each offer includes
A freelancer can be a good fit for a well-defined specialist task or an existing team. An agency can bring several disciplines and coordinate a broader project. Check whether product discovery, UX, testing and deployment are included or remain your responsibility. Add the cost of missing roles when comparing quotes.
Evaluate continuity and communication
Ask how progress is demonstrated, how availability is managed and who can resolve an issue after launch. A small team can communicate directly while also sharing knowledge. A larger organisation does not automatically guarantee continuity. Assess the actual people assigned to the work and the documentation they will provide.
Choose for your level of uncertainty
A narrow requirement with strong internal management may suit a freelancer. A product requiring several disciplines may benefit from a coordinated team. In either case, agree deliverables, ownership, payment milestones and a change process. Use a focused first milestone to check the collaboration before increasing the commitment.