Approval rules people actually follow
Most chains fail because they ask the wrong person, at the wrong time, with the wrong amount of context.
MandoClaro

Approval chains die of politeness. Everyone is copied. Nobody is accountable. The bill sits until someone is brave enough to ping the CFO.
A rule people follow is short, specific, and already in the tool where the bill lives.
One owner per amount
Route by amount and vendor, not by habit. A €400 software renewal should not wait on the same desk as a €40,000 contractor.

Keep the context with the request
The approver should see the invoice, the policy, and the remaining budget without opening three tabs. If they have to hunt, they will delay.
MandoClaro puts the ask, the bill, and the ledger line in one place so the yes or no is a decision, not a research project.