Which part of project planning do you find the most challenging?

There are probably three big challenges related to planning that I've had to deal with multiple times in my career.

The first is helping leadership understand that effective planning and testing assumptions, done well, don't actually slow the project down. Maybe planning takes a little longer, but we're building the right thing. Why do we have time to do the work three times but it's not okay to spend a little more time on planning, do it once, and get it right the first time, faster than doing it three times?

The second challenge is part of the first, but also presents itself at other points during the project. Data. You don't need a data scientist (normally), but you often need data to validate your assumptions and make sure you're solving the right problem. You need the right data, preferably complete and accurate. If you're passing data between systems, you need the same fields to exist in both systems if you're not transforming it into something new, first. Data migrations 1) take longer than you think, 2) do need testing and validation, and 3) can affect and be affected by network bandwidth.

Third is getting people to estimate both their effort and the expected duration. Don't tell me that the task is going to take two hours of work, and leave it at that, if you can't start it for three days and you have to spread out the work over four days. Assuming you finish your other work on schedule and nothing new comes up.

Hello Francisco Herrera


I think The most challenging part of project planning is accurate estimation under uncertainty.
Time, cost, and scope are tightly linked, yet they’re usually defined with incomplete information. Scope evolves, risks (especially human and organizational ones) are underestimated, and productivity is often assumed rather than measured. This leads to optimistic schedules and budgets that only reveal their flaws late in the project, when corrections are costly.

the hardest part is aligning assumptions early, especially around scope and dependencies.
Not because we can’t plan them, but because everyone comes in with different mental models of “what’s included” and “how things will flow.” If those assumptions aren’t surfaced and challenged upfront, the plan looks solid on paper and fragile in reality.
Once that alignment is real, the schedule, risks, and resources become much easier to manage, even in rigid environments like Waterfall.

Cost estimation has been the most challenging aspect for me, largely due to the many uncertainties associated with managing projects in remote communities. These include the extensive timelines and administrative requirements for securing funding through Indigenous Services Canada, as well as approvals from Chiefs and Council.

In addition, procurement and logistics add significant complexity, particularly when materials must be transported over winter roads. Variability in winter conditions and shorter ice road seasons driven by warming trends further increase cost and schedule risk. As a result, cost control and procurement planning are major challenges that require conservative estimating, contingency planning, and close coordination with all stakeholders.
If you’d like, I can also tighten this for LinkedIn, a report, or a resume version.

One of the biggest challenges is deciding when to commit to dates versus costs (the Triple constraints of Scope, Time, and Cost).

• Stakeholders usually want all three fixed early: a firm date, a low budget, and a full feature set. Committing too early could lead to underestimating the complexity of the scope.
• If you lock in a date before the costs are fully understood, you often end up "crashing" the schedule (at a high cost) or cutting quality to meet the deadline.

Another one is balancing resources across multiple projects, like playing a high-stakes game.

• When a key player (like a specialized engineer or a senior designer) is split between three projects, there is a high chance that their productivity will drop.
• Resource leveling comes in handy, adjusting the project schedule to address allocations. It almost always results in a delayed finish date, which brings you right back to the commitment dilemma mentioned above.

Dealing with Unknown Unknowns".

• RAID logging requires constant vigilance. A project plan is only as good as its underlying assumptions.
• Estimation techniques have limited accuracy, adding complexity to the planning and implementation.

From my experience as a marketing team lead, the hardest part of planning is assigning resources and managing priorities. Campaigns often overlap, the team has limited capacity, and client needs can change. Getting the balance right between what’s planned and what can actually be done takes careful coordination and clear communication.