Wasted ad spend rarely comes from one catastrophic error. The eleven most common leaks: launching broad match with no negative keyword list, never reading the search terms report, sending every ad to the homepage, running with no conversion tracking, switching to Smart Bidding too early, one ad group with 200 keywords, leaving the Display Network on inside a Search campaign, ignoring location and language settings, skipping ad extensions, never checking budget pacing, and never pausing anything. Together these routinely account for 40 to 60 percent of a small account's spend.