Design cost centres, budgets and rules

Structure it once, properly. The decisions here are the expensive ones to change later.

The order matters. Cost centres first, because everything else points at them. Budgets next, on the monetary cost centres that need controlling, not on all of them. Then the approval rules that decide what happens when a cart crosses a line, and finally the personal limits that decide how much ordering never reaches an approver at all.

Three decisions here are hard to reverse: the cost-centre codes, which have to match the customer's ERP and are unique across your tenant; each centre's budget type (monetary or tracking only), which is fixed when the centre is created; and whether a rule refuses or routes spend that crosses a limit. Get those from the customer in writing before you configure anything.

• Cost centres: master data per organisation, accountable contact, restrictions.
• Budgets: amount, period, carry-over, and what happens when it runs out.
• Approval rules: which spend needs a signature, whose, in which order.
• Buyer spend limits: one personal limit per contact, and the rule that reads it.