CAC is most meaningful when compared against Customer Lifetime Value (LTV) — a common health benchmark is an LTV:CAC ratio of at least 3:1, meaning a customer generates at least three times what it cost to acquire them over their relationship with the business.
CAC can be calculated per channel (blended CAC vs. paid-channel-only CAC) and tends to rise over time within a channel as easy, low-cost audiences are exhausted — which is why diversifying acquisition channels and improving conversion rate (rather than only increasing spend) are common levers to keep CAC sustainable.