The question should I subcontract planning is badly formulated. It is a seller's question, and the honest answer is not always yes. The right question is different: which planning model fits the real needs of this project and this company? Sometimes the answer is an external consultancy; sometimes it is an in-house engineer; and sometimes a basic in-house schedule is simply enough.

The variables that decide

Five factors determine which model is appropriate. The decision does not depend on just one of them, but on their combination:

  • Continuity and workload volume. This is the dominant factor. A full-time position only pays off if there is sustained workload to keep it occupied throughout the year.
  • Project complexity and risk exposure. Number of activities, interdependencies, interfaces between contractors, delay penalties and cash exposure. Size is not the same as complexity.
  • Required specialisation. Routine scheduling is not the same as forensic delay analysis, 4D planning or Monte Carlo schedule risk analysis.
  • Need for independence. In claims, arbitrations or in the role of Owner's Engineer, objective analysis is needed, which an internal team with a conflict of interest cannot always provide.
  • Cost structure. Fixed cost, including salary, social charges, overhead and idle time, versus variable cost, where payment is made only for the necessary work.

When you do not need professional planning

It should be said clearly: not every project requires a Primavera P6 schedule. In small, short-duration works with few activities, limited interdependence and low contractual exposure, a well-prepared Gantt chart in a spreadsheet or simple tool, maintained by a competent site manager, is a proportionate solution. Oversizing planning on a trivial project is as inefficient as not planning a complex one.

The important nuance is that the threshold is not set by value, but by complexity. A modest-value project with aggressive delay penalties, many simultaneous fronts or a tight supply chain may need professional planning; and a higher-value project that is linear and without critical interfaces may not. The useful question is not how much the works are worth, but how much a sequence error or delay costs on this project.

Even so, even in these cases, a few hours from a specialist to set up the initial structure usually pays for itself. What is rarely justified here is a recurring full-time service.

When an internal planner is convenient

Hiring an in-house planning engineer is the best option, and no honest consultancy should deny it, when these conditions exist:

  • A stable and simultaneous project portfolio that sustains the workload of a full-time position. With high utilisation, the hourly cost of an internal resource is lower than that of an external one.
  • Long-duration programmes where stability can be offered to an employee.
  • When planning is a core and constant business function, not an occasional peak.

If your company is in this scenario, the decision is clear: internalise. Fixed cost stops being a problem when utilisation is high.

When subcontracting makes sense

Subcontracting wins when the workload is irregular or the need is specialised:

  • Fluctuating project volume, which is the norm in construction, energy and infrastructure. An internal planner pays off poorly if they spend months underused between peaks.
  • Peaks and critical moments: tender preparation, major milestones, recovery plans or claim defence, where extra capacity is needed temporarily without increasing permanent staff.
  • Specialised needs used occasionally: forensic delay analysis, 4D BIM planning, Monte Carlo risk analysis, claims support and extensions of time, or EOT. Maintaining these capabilities in-house is expensive when they are used only occasionally.
  • Independence and objectivity: when analysis is required that is not committed to the internal position.
  • Fast mobilisation: capacity available immediately, without the recruitment cycle and learning curve of a hire.
  • Lack of experience and proactivity. If there are no senior employees with leadership and proactive capability, it may be a good idea to subcontract an expert temporarily to guide the department, bring new ideas or propose automation and standardisation.

In these cases, the variable cost and multi-sector experience of a specialist clearly compensate compared with a fixed position.

The model mature companies usually adopt: the hybrid

In practice, the choice is rarely absolute. Many well-managed organisations combine both models: a small internal core that guarantees continuity and business knowledge, reinforced with external specialists for workload peaks and specialised work. This covers the baseline with efficient cost and provides access to advanced capabilities without permanently loading them into the structure.

The decision, at root, is the same as with any resource: which part of demand is stable and deserves fixed capacity, and which part is variable and should be covered flexibly.

Where PlanBuilt fits, and where it does not

To be consistent with the above: PlanBuilt operates in the subcontracting space, and its model, a senior engineer providing judgement supported by a technician embedded in the project, is designed precisely for scenarios of fluctuating volume, peak reinforcement and specialised work, such as 4D planning, schedule risk, automation and claims support.

But the honest recommendation is the one that follows from the framework: if your company has a stable portfolio that sustains a full-time position, the sensible option is to hire an internal planner, not a recurring external service. And if your project is small and simple, a good initial schedule and simple follow-up will probably be enough. Using a consultancy makes sense when the workload is irregular, the need is specialised or independence is required, not as a universal rule.

Not every project needs a professional planner; not every company should internalise it; and not every company should subcontract it. If you are unsure which situation your case falls into, at PlanBuilt we can help you analyse it, even if the conclusion is that you do not need us.