How to Reduce Wasted Ad Spend in Google Ads

Every Google Ads account wastes money. The question is how much. Even well-managed accounts typically have 10-15% of spend going to searches, audiences, and placements that will never convert. Poorly managed accounts? That figure can exceed 40%. This guide covers the practical strategies that Spires Digital uses to systematically identify and eliminate wasted ad spend — from search term audits and negative keywords to audience exclusions and schedule adjustments.

Search Term Audits: Your First Line of Defence

The search terms report reveals exactly what people searched before clicking your ads. It is the most valuable report in Google Ads for identifying waste, yet many advertisers check it only occasionally — or not at all.

How to Conduct an Effective Search Term Audit

• Pull search terms for the past 30 days, filtered by cost (highest first)
• Identify terms that received clicks but zero conversions
• Flag terms with conversions but at a CPA well above your target
• Look for patterns — recurring themes often indicate systematic waste
• Check branded terms appearing in non-brand campaigns (cannibalisation)

The Hidden Search Terms Problem

Google now hides a growing percentage of search terms for privacy reasons. In many accounts, 30-50% of clicks come from terms marked "Other search terms." While you cannot see these individual queries, you can:

• Use the visible terms to identify patterns and create proactive negatives
• Cross-reference your search terms data with GA4 landing page reports to identify underperforming pages
• Monitor performance at the ad group level — sudden CPA spikes often indicate hidden irrelevant queries

Negative Keywords: Systematic Waste Prevention

A comprehensive negative keyword strategy is the most effective way to reduce wasted spend. But most accounts apply negatives reactively — adding them only after money has been wasted.

Proactive Negative Keyword Approach

• Build a universal negative list before launching any campaign (jobs, free, DIY, tutorials, etc.)
• Create industry-specific negatives based on your business model
• Use shared negative keyword lists applied at the account level
• Add brand negatives to non-brand campaigns to prevent cannibalisation
• Review and update weekly for the first month, fortnightly thereafter

A single well-placed phrase match negative can block dozens of irrelevant queries that would otherwise cost you money indefinitely.

Audience Exclusions: Cutting the Right Traffic

Not all traffic is equal. Audience exclusions prevent your ads from showing to people who are unlikely to convert, even if their search query is relevant.

Audiences to Consider Excluding

• Existing customers: If your goal is new customer acquisition, exclude converters from the past 90-180 days
• Job seekers: Exclude the "Job seekers" in-market audience from commercial campaigns
• Students: If you sell to businesses, exclude education-related affinity audiences
• Remarketing exclusions: Exclude recent website visitors from cold prospecting campaigns to avoid paying twice for the same user

Observation vs Targeting Mode

Before excluding an audience entirely, set it to "Observation" mode to see how it performs. If the audience consistently underperforms (high CPA, low conversion rate), then add it as an exclusion. Data-driven exclusions are always better than assumptions.

Ad Schedule Adjustments

Not every hour of the day and day of the week performs equally. Analysing performance by time allows you to reduce bids or pause ads during low-converting periods.

How to Identify Waste by Schedule

• Pull a day-of-week and hour-of-day report from Google Ads
• Compare conversion rates and CPAs across different time segments
• For B2B campaigns, weekends and evening hours often have significantly worse performance
• For e-commerce, late-night hours may have high bounce rates with few purchases

Implementation

• Use bid adjustments to reduce spend during underperforming hours (not eliminate entirely)
• Start with a -25% to -50% adjustment for consistently poor time slots
• Review monthly and adjust based on seasonal patterns
• With Smart Bidding, the algorithm handles time-of-day adjustments automatically — but ad scheduling (turning ads off entirely) still works

Placement Reports for Display and Video

If you run Display or YouTube campaigns (or Performance Max with display assets), the placement report shows exactly where your ads appeared. This is often where the biggest waste hides.

Common Placement Waste

• Mobile app placements: Accidental clicks from games and utility apps
• Low-quality content sites: Made-for-advertising sites with no real audience
• Children's content: YouTube channels or websites with audiences that will never convert
• Parked domains: Expired domain sites with no genuine traffic

Cleaning Up Placements

• Exclude the mobile app category entirely from most Display campaigns
• Review placement reports weekly and exclude poor-performing sites
• Create a shared placement exclusion list for sites you never want to appear on
• Use content suitability settings to avoid sensitive or inappropriate content

Geographic Performance Analysis

If you target a broad area, some locations will significantly outperform others. Analysing performance by geography lets you focus budget where it works best.

• Pull geographic reports at the region, city, or postcode level
• Identify locations with high spend but low conversion rates
• Apply negative bid adjustments (-20% to -50%) for underperforming areas
• Exclude locations that consistently waste budget with zero conversions
• Consider creating separate campaigns for your best-performing regions

Device Performance Optimisation

Desktop, mobile, and tablet traffic often convert at very different rates. While Smart Bidding accounts for device differences, you can still make manual adjustments.

• Review conversion rates by device across all campaigns
• If mobile conversion rates are significantly lower, check your mobile landing page experience
• For B2B campaigns, desktop often outperforms mobile significantly — consider bid adjustments
• For lead generation with phone calls, mobile may outperform — adjust accordingly

For more on budgeting effectively, see our guide on calculating your Google Ads budget.

Building a Waste Reduction Routine

Reducing wasted spend is not a one-time project — it is an ongoing discipline. Here is the routine we follow at Spires Digital for every client account:

• Weekly: Search term review, placement review, conversion tracking verification
• Fortnightly: Audience performance analysis, negative keyword updates
• Monthly: Geographic analysis, device analysis, ad schedule review
• Quarterly: Full account audit, bidding strategy review, campaign structure assessment

Frequently Asked Questions

Cutting wasted spend is often the fastest path to better Google Ads performance — faster than new ad copy, new landing pages, or increased budgets. If you want a professional audit of your account's waste, get in touch with Spires Digital or book a free strategy call via Calendly — we will show you exactly where your budget is being wasted and how to fix it.