Optimization means tweaking bids, pausing keywords, and testing new ads. Restructuring means rebuilding how the campaign is organized. Signs you need a restructure include ad groups with too many unrelated keywords, ads that do not match the keywords they are grouped with, landing pages that do not connect to the ad message, and quality scores stuck below five across the board. If adding negative keywords and adjusting bids is not moving the numbers, the problem is often structural. So what do you think is the clearest sign that a campaign needs more than just minor adjustments?