Your question is Assess Marketing Channel Saturation. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
You are evaluating a paid acquisition channel that has been a meaningful source of pipeline. Spend can still be increased, but you want to know when additional budget stops producing efficient incremental results and starts driving weaker lead quality or higher acquisition costs.
What metrics would you look at to determine if a specific marketing channel is saturated?