Track channel-specific CAC separately from blended CAC. Blended CAC hides expensive channels. When a channel's CAC exceeds your target LTV ratio, it is time to reallocate.
Strong answers cover: calculating fully-loaded CAC (including salaries, tools, creative), segmenting by channel and campaign, tracking CAC:LTV ratio, identifying diminishing returns per channel, and balancing short-term CAC optimisation with long-term brand building. Best candidates discuss blended vs channel-specific CAC and how to account for multi-touch attribution in the calculation.
Tests financial literacy and strategic thinking. Marketers who cannot tie spend to acquisition cost are spending blindly. Ask: "How do you handle channels where CAC is high but customer quality is also high?"