It's the question I get asked more than any other by e-commerce owners: should I just run Performance Max, or keep my campaigns separate? It came up again in the industry press this week, and the honest answer is the one nobody really wants to hear. It depends. But let me explain what it depends on, because that's the bit that actually helps you decide.
What Performance Max Is Really Selling You
Performance Max takes Shopping, Search, Display, YouTube, Discover, and Gmail, throws them in one campaign, and lets Google's automation decide where your money goes and who sees your ads. The pitch is simple: give Google your products, your budget, and a goal, and it'll do the rest across every channel at once.
For a lot of stores, that genuinely works. Google's machine learning is good at finding buyers, and PMax can surface conversions you'd struggle to find manually. When it clicks, it's a powerful, low-maintenance way to drive sales.
The catch is the trade-off you're making: control and visibility. PMax is, by design, a bit of a black box. You can't see exactly which search terms triggered your ads. You can't easily separate what Shopping is doing versus Display. You're trusting the system, and when the system is spending your money, trust needs to be earned.
When Performance Max Is the Right Call
PMax tends to work best when a few things are true.
You've got a decent budget and enough conversion data for Google's automation to actually learn from. Starve it of data and it flails. Feed it well and it improves.
Your product feed is in good shape—accurate titles, clean images, sensible product types, correct pricing. PMax leans heavily on your feed, so feed quality is doing most of the heavy lifting whether you realise it or not.
And your margins have room to absorb some inefficiency. PMax will occasionally spend in places you wouldn't choose, and you need to be comfortable that the overall return still works.
If that's you, PMax can be brilliant. Set it up properly, feed it well, and it'll do a lot of the work.
When Separate Campaigns Win
Now the other side, because this is where I part company with the "just run PMax" crowd.
If you need to see what's actually happening—which search terms convert, which products carry the account, where the waste is—then keeping standard Shopping and Search campaigns separate gives you control that PMax simply won't. You can add negatives, adjust bids by intent, protect your brand terms, and ring-fence your bestsellers.
If your budget is tight, separate campaigns let you put money exactly where the return is, rather than handing Google a pot and hoping. And if you've got high-value products or thin margins, that precision matters enormously.
There's also a quiet problem with PMax that doesn't get talked about enough: it loves to claim credit for sales that would've happened anyway, particularly from brand searches and existing customers. Separate campaigns make it far harder for that to hide.
The Real Decision
So here's how I'd actually frame it. PMax is not better or worse than separate campaigns in the abstract. It's a different bargain. You're trading visibility and control for automation and reach.
For some businesses that's a great deal. For others—especially those where every pound of ad spend needs to be accountable—it's the wrong one. The mistake I see most often isn't choosing one over the other. It's choosing PMax because it's the default Google nudges you towards, without ever asking whether your business can afford to give up the control.
And there's a wider point here worth holding onto. Google keeps steadily reducing the number of levers you can pull yourself—retiring Display, pushing automation, folding everything into fewer, smarter campaign types. The direction of travel is towards trusting the machine. Sometimes that's right. But knowing when to trust it and when to keep your hands on the wheel is most of what good account management actually is.
What I'd Do
If you're running an e-commerce store and you're genuinely unsure, my honest advice is this: don't pick based on what's fashionable or what Google recommends. Pick based on how much visibility your business needs to make good decisions.
Test it properly if you can—run PMax against a structured separate setup and compare the real numbers, not the ones the campaign reports back to itself. Watch where the spend goes. And whatever you run, get your product feed right first, because both approaches live or die on the quality of the data you feed them.
The clever tooling will keep changing. The question underneath it won't: is your money working as hard as it could be, and can you actually see that it is? Answer that honestly, and the PMax decision answers itself.