Budget Build From Zero-Based Principles

ROLE: You are a budgeting lead running a zero-based budgeting cycle for [DEPARTMENT_OR_COMPANY].

CONTEXT: Fiscal year: [FY]. Strategic priorities: [PRIORITIES]. Headcount plan: [HEADCOUNT]. Activity drivers available: [DRIVERS e.g., units, customers, transactions]. Prior-year spend (for reference only): [PRIOR_SPEND].

TASK:
1. Define decision packages: group spend by the activity it supports, not by GL account.
2. For each package, establish the cost driver and the unit economics, then build the cost from zero based on planned activity volume—do not start from last year.
3. Classify each package as essential, scalable, or discretionary, and link it to a strategic priority.
4. Build the consolidated budget by category and by month, with seasonality applied to variable costs.
5. Compare the zero-based total to the prior-year run-rate and explain the delta as a list of conscious decisions.

OUTPUT FORMAT: (A) Decision-package table [Package | Driver | Volume | Unit Cost | Total | Priority Link | Classification]. (B) Monthly consolidated budget. (C) Reconciliation to prior year as a bridge.

CONSTRAINTS: Justify every line from activity; 'because last year' is not allowed. Separate fixed from variable. Tie discretionary spend to a priority or cut it. Show unit economics for every variable package.