Lessons From 15 Years in Paid Media: The Mistakes That Still Haunt Me (and How You Can Avoid Them)

I started my career in paid media back in 2011 at a small PPC agency called Periscopix. It was, in many ways, a much simpler time. Performance Max didn’t exist. Campaign management meant making one bid change a day. You had full control.

It was also the year that Prince William and Kate Middleton got married, and the year Charlie Sheen made headlines for all the wrong reasons. Simpler times indeed.

Over the past 15 years, I’ve made (and witnessed) plenty of mistakes in paid media. Some of them were painful, some were expensive, and all of them taught me lessons that I still carry with me today.

Here are the big ones — and what you can learn from them so you don’t repeat my errors.

1. Always Get It in Writing

Early in my career, I worked with a major watch retailer. They were a dream client: open to testing new features, collaborative, and easy to work with.

One day, I phoned my contact and suggested increasing budgets because performance was strong. She agreed — “let’s add an extra £10K for October.” I made the changes, felt great about my proactive decision, and went on holiday to Las Vegas.

When I returned, I was sick and couldn’t work for a week. During my time off, the account overspent by £10K. When my boss confronted me, I explained it had been approved verbally. But my contact denied the conversation had ever happened.

I had nothing in writing. The client distanced themselves, and I got the dreaded “I’m not angry, just disappointed” talk from my manager.

🎓Lesson: However good the relationship, always confirm changes in writing. Emails, tickets, Slack messages — anything is better than relying on memory or goodwill.

2. Always Double-Check (and Then Check Again)

This one didn’t happen to me personally, but it’s a nightmare scenario.

A campaign manager at a large agency was asked to launch a big Meta campaign for a beauty retailer just before a bank holiday weekend. The budget was £150,000 for May, with a daily cap of just over £4,000.

In the Friday rush, they accidentally set the campaign budget at £150,000 instead of the lifetime budget spread over the month. The campaign went live on Saturday as planned. By Tuesday morning, the entire budget had been spent — in three days.

🎓Lesson: Never rush a launch. Always double-check settings (budget types, dates, placements), and if possible, have a colleague cross-check before pushing campaigns live.

3. The £25,000 Job Interview Mistake

At Periscopics, we sometimes asked candidates to prepare a strategy for a well-known retailer. Strong candidates would use Google Ads Keyword Planner, mock up ads, and show how they’d approach campaigns.

One candidate went above and beyond — too far, in fact. He didn’t just mock up the campaigns. He accidentally launched them. By the time anyone noticed, he’d spent around £2,500 (rumors exaggerated it to £25,000).

The company did the right thing: they hired him, supported him, and even raised his salary to help cover the cost. But it was a hard lesson in the importance of checking accounts before and after setup.

🎓Lesson: Whether you’re preparing a test, an interview, or a live campaign, triple-check that campaigns aren’t accidentally switched on. And always log back in after setup.

4. The Father’s Day Disaster

This one still stings.

In 2022, just a year and a half into running my consultancy, we landed a big client in the gifting experience space. Father’s Day was a peak season, so the pressure was high. Their PPC team was very junior, and we were brought in last-minute to advise.

Red flags came quickly:

• They insisted on broad match keywords.
  
• Every campaign had a £500/day budget, multiplied across 10 campaigns.
  
• They wanted to launch on a Friday at 3 p.m.
  

We strongly advised caution, documented everything in writing, and warned against the plan. They went ahead anyway.

By Monday, £40,000 had been spent with zero sales. The furious CEO called me directly. We lost the client (and £12,500 in unpaid consultancy fees).

🎓Lesson: Trust your instincts. If a client refuses to listen to reason, it’s not a partnership worth keeping. Spot the red flags and walk away.

Quickfire Mistakes to Avoid

Beyond the big horror stories, here are a few smaller — but just as painful — pitfalls I’ve seen:

• Linking to the wrong Meta account. Easy to do if you manage multiple clients. Always check catalog feeds before publishing.
• Hitting “Apply All” in recommendations. I once had a client unknowingly switch all keywords to broad match. Chaos followed.
• Not leaving cover notes before holiday. I once covered an account on Christmas Eve with zero context. It didn’t go well.
• Emailing the wrong contact. I accidentally sent a pitch deck to someone’s old employer, causing major fallout.

Key Takeaways

• Always confirm in writing.
• Always check (and have someone else check).
• Never launch on a Friday.
• Go slower when under pressure — not faster.
• Learn from mistakes, but don’t repeat them.
  

And finally, remember: we’re not brain surgeons. We’re not saving lives. Paid media mistakes can be stressful and expensive, but they’re rarely career-ending if you learn and improve.

Give yourself a break. Mistakes happen. What matters is making sure they don’t happen twice.

Kat Sale is Co-Founder of House of Performance, a paid media agency based in Clerkenwell, London. This article is based on Kat’s talk at Hero Conf UK in April 2025, which you can watch in full for free.