TCO Total Cost of Ownership — the full cost including purchase price, quality, maintenance, and risk over the entire lifecycle.
Incremental Cost Only the costs that change with the decision — like counting just the gas when comparing cars, ignoring insurance and maintenance.
Stranded Overhead Fixed costs (buildings, managers, systems) you still pay after outsourcing — like keeping the garage after selling the car.
Supply Market Depth How many real alternatives exist. A market of one supplier is not a market — it's a dependency dressed as a contract.