The lease term, the payroll in the hiring plan, fit-out and equipment, local accounting and insurance, and the legal and document work. The business commitments usually dwarf the case costs and, unlike them, continue whether or not the plan is met.
Test the plan against a slow year
Model the operation on lower revenue than the plan assumes and check whether the lease and the first hires remain affordable, since an operation that quietly stalls is difficult to present at the one-year point. Ask counsel to itemize the initial work, dependent assistance and any later evidence responses separately from a possible extension. Confirm official charges at the time of the relevant step.
Add one further figure to that stress test: the cost of an orderly withdrawal. If the operation does not develop as planned, the business will face lease obligations, notice periods, equipment commitments and possibly redundancy costs, and those are far easier to size at the point the commitments are being made than at the point they must be met. Knowing that number also improves the commitments themselves, since a break clause or a shorter initial term is usually negotiable at signature and never afterwards.
Hypothetical example: a packaging manufacturer prices the exit alongside the entry before signing a lease, and the exercise leads to a shorter initial term at slightly higher rent, which proves to be the more valuable of the two terms when the first year runs behind plan.