Common Performance Max Mistakes in 2026 (Yes, These Still Happen)

Anthony McGrath • February 19, 2026

By 2026, Performance Max mistakes are rarely technical. They’re strategic. The platform does exactly what it’s told — sometimes a little too well.


Here are the most common Performance Max optimisation mistakes we still see, with examples that explain why results go sideways.


Mistake #1: One Performance Max Campaign Doing Everything

Trying to make one Performance Max campaign handle every goal usually leads to confused delivery and inflated CPAs.


What typically happens:


  1. Google prioritises the easiest conversions (usually brand traffic)
  2. Prospecting gets underfunded
  3. Reporting becomes impossible to interpret.


 “Performance Max isn’t confused — it’s just following bad instructions very enthusiastically.


In a mid-sized ecommerce account, splitting one all-in-one campaign into two clear objectives:


  • Prospecting (new customers)
  • Efficiency (existing demand)


Resulted in:


  • 31% lower CPA
  • Smoother spend distribution
  • Clearer insight into what was actually driving growth

Mistake #2: Letting Auto-Created Assets Run the Show



Auto-created assets are useful — until they become the only assets.


Common symptoms include:


A. Generic headlines with zero differentiation
B. Auto-generated videos made from stock images
C. Ads that technically exist but emotionally don’t

“Auto-generated ads are what happens when Excel tries copywriting.”

A B2B SaaS advertiser replaced auto-created text and video with human-written copy and two simple product videos. 


Within 30 days:


1. CTR increased 38%

2. Cost per qualified lead dropped 24%

3. YouTube inventory started converting,

not just “existing”

Mistake #3: Optimising for the Wrong Conversions

Performance Max will optimise for whatever you define as success — even if that success is meaningless.


The most common offenders:


  • Newsletter signups
  • Low-intent contact forms
  • Pageview-based micro conversions


One service-based account removed low-quality actions from its primary optimisation goal and focused only on revenue-driving leads.


The result:


A. Revenue per lead increased 41%
B. CPA increased slightly (
+6%)
C. Sales team complaints decreased dramatically (rare but powerful metric)


Optimising for low-intent conversions is like giving your campaign a gold star ⭐ every time someone looks at the homework instead of doing it.

Mistake #4: Never Refreshing Creative

Performance Max doesn’t get bored. Audiences do.


Accounts that leave creative untouched for months typically see:


  1. Gradual CPA creep
  2. Falling CTR
  3. “Performance just dropped for no reason” conversations


A DTC brand refreshing creative every
30–45 days saw:


  • Spend scale +62%
  • CPA remain stable
  • Performance recover without touching bidding

Mistake #5: Blindly Applying Google Recommendations

Recommendations are suggestions — not commandments.


Following every recommendation often leads to:


A. Budget increases
B. Broader targeting
C. Less control, not more performance

One advertiser applied all recommendations for 30 days:


  • Spend increased 45%
  • Conversions rose 12%
  • CPA worsened 29%

Rolling back non-essential changes restored performance within two weeks.

Google recommendations are helpful… just not always for your bank balance.

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