TL;DR: Most wasted Google Ads budget comes from seven fixable mistakes, and broken conversion tracking is the one that quietly causes the other six to go unnoticed. Work through this list against your own account. Each one has a practical fix you can do this week.
We audit Google Ads accounts for a living, and the surprising part is not how bad the worst accounts are. It is how similar they are. The same handful of mistakes shows up in account after account, from plumbers spending 1,500 dollars a month to contractors spending 15,000. Here are the seven we see most, in the rough order of how much they cost.
1. Conversion tracking is broken, so everything else is guesswork
This is the big one, and it is why we check it first in every audit. If calls and form fills are not counted correctly, Google optimizes toward clicks instead of customers, your reports are fiction, and every other decision in the account is made blind. Broken tracking does not just waste money directly. It hides the other six mistakes on this list. If you only fix one thing, fix this. We wrote a complete guide to conversion tracking including a 15 minute audit you can run yourself.
2. No negative keywords, so junk searches eat the budget
Open the search terms report in an unmanaged account and you will find job seekers, DIY researchers, and students clicking ads all day. “Plumbing jobs near me.” “How to fix a water heater.” Every one of those clicks costs the same as a click from a real buyer. The fix is a negative keyword list that grows weekly. We covered the whole method, including a paste-ready starter list, in our negative keywords guide.
3. Broad match left on default with no guardrails
Google has steadily loosened how keywords match searches, and new campaigns lean broad by default. Broad match can work, but only on top of solid conversion data and a strong negative list. Without those two things it simply spends your budget exploring, and you fund the exploration. Check your match types. If everything is broad and your tracking is shaky, that combination alone can explain a bad quarter.
4. Sending ad clicks to the homepage
Someone searches “water heater replacement” and lands on a homepage about your company history and your full service list. They wanted one thing. Now they have to hunt for it, and most will not. Every ad should land on a page that matches the search behind it, with a phone number visible before scrolling. This is the cheapest conversion rate improvement available in most accounts, and we broke down the full click-to-booked-job path in our conversion optimization guide.
5. Counting the wrong things as conversions
Page views. Button clicks. Every form submission counted separately, so one enthusiastic visitor logs three leads. Inflated conversion counts feel good in a report and poison the bidding. A service business should count phone calls over a minute, real form submissions, and booked appointments. Nothing else. If your conversion numbers look great but the phone is quiet, this is usually why.
6. Set and forget
Google Ads is not a crockpot. Search behavior drifts, competitors change bids, Google changes matching, and fresh junk arrives in the search terms weekly. An account that nobody has touched in three months is an account slowly reverting to waste. The core weekly work takes well under an hour: read the search terms, adjust the negatives, check the budget flow. What that ongoing work should look like is exactly what our Google Ads management guide covers.
7. Accepting Google’s automated recommendations blindly
The recommendations tab is not neutral advice. It is a mix of genuinely useful suggestions and prompts that mostly increase your spend, and Google grades your account’s “optimization score” on whether you accept them. Auto-applied recommendations are how accounts wake up with broad match keywords they never chose. Review each suggestion on its merits, and turn auto-apply off. An optimization score of 100 percent is not a goal. It is a warning sign.
Not sure these seven are your problem? Start with the four-state triage for Google Ads that are not working, which tells you whether you are dealing with a serving issue, a click issue, a conversion issue, or a tracking issue before you change anything.
The pattern behind all seven
Every mistake on this list survives for the same reason: nobody is measuring properly, so nothing looks obviously wrong. The account spends, some leads arrive, and the waste hides in the gap between what happened and what got counted. That is why our audits always start at tracking and work outward. If you want to know which of these seven are active in your account right now, our free 2 minute Google Ads check gives you a plain English answer, no login required.
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