Do You Factor in Customer Lifetime Value When Calculating Your Ads ROI?

When I speak to small business owners who are running their own Google Ads, one thing I often notice is this: when they’re working out whether their ads are “working,” they usually look only at the first sale.

On paper, that makes sense. You run an ad, someone clicks, and they make a purchase. So, you look at that order to see if it covered the ad cost.

But here’s the problem: if you stop there, you’re probably undervaluing your ads. Why? Because many customers don’t just buy once. They come back again. And again. And sometimes stay with you for years.

That’s where Customer Lifetime Value (CLV or LTV) comes in.

What Is Customer Lifetime Value?

Put simply, LTV measures the total revenue you can expect from a customer across their entire relationship with your business.

Instead of just looking at the first transaction, LTV looks at the bigger picture.

• A florist might see a £30 order for a birthday bouquet. But if that customer goes on to sign up for a monthly subscription, they’re suddenly worth hundreds of pounds over the year.
• A chiropractor might see an initial £50 consultation. But many of those new patients will return for a course of treatments worth £500+.
• A SaaS company might see a £20/month subscription. If the average customer stays for 18 months, that’s £360 - not £20.

Without factoring in LTV, you risk making decisions based on a much smaller number than the true value of your customer.

Why Focusing on The First Sale Can Be Misleading

Let me give you an example.

I have recently been working with a health SaaS business offering both monthly and annual subscriptions. They were reviewing their Google Ads performance and focusing on the initial payment from a new customer.

It cost them around £15 in ad spend to acquire a new monthly subscriber, and the monthly subscription fee was £20 per month.

On the surface, that didn’t look particularly impressive. Yes, they were technically covering their acquisition cost within the first month, but once you factored in product costs, software costs, and general business overheads, the margin looked slim. They were questioning whether Google Ads was really worth it.

But when we zoomed out and looked at the average lifetime value, the picture changed completely.

The average monthly subscriber stayed with them for two years.

So instead of being worth just £20, that customer was actually worth:

£20 × 24 months = £480 total revenue

Now compare that to the £15 acquisition cost, and suddenly the numbers look very different.

Instead of generating £20 from a £15 investment, they were generating £480 from a £15 investment.

That’s a completely different conversation.

Why Annual Subscribers Were Even More Valuable

It became even more interesting when we looked at their annual subscription option.

Their annual plan worked out at around £15 per month equivalent, billed annually at £180 per year, and customers on this plan stayed with them for an average of four years.

So the average lifetime value of an annual subscriber was:

£180 × 4 years = £720 total revenue

If the acquisition cost was still around £15 per customer, that meant a £15 investment was generating £720 in revenue over time.

This insight completely changed the strategy. Instead of just looking at whether ads were profitable in the first month, we could see the real long-term value.

It also meant we could confidently prioritise attracting more annual subscribers, because they were significantly more valuable to the business.

Without factoring in lifetime value, they were close to switching off Google Ads entirely, not because it wasn’t working, but because they were looking at the wrong timeframe.

Different Types of Businesses, Same Principle

This isn’t just about SaaS. Whatever type of business you run, LTV can give you a truer picture:

• Florist with subscriptions: One £25 order looks unprofitable against a £15 ad conversion. But if the customer stays on a 12-month subscription, they’re worth £300+.
• Retail boutique: A £60 first order might barely cover your costs. But if repeat buyers spend £200+ over the year, the ads look much healthier.
• Service businesses: A plumber or electrician might get a £100 call-out. But once someone trusts them, they’ll come back whenever they need help, and often recommend them to friends.

The pattern is the same: if you only count the first sale, you’ll almost always undervalue the role ads are playing in building your customer base.

This isn’t a magic bullet, and every business is different, but factoring in lifetime value gives you a much clearer sense of whether your ads are truly working and helps avoid making decisions based on an incomplete picture.

How LTV Fits Alongside MER

In my recent blog about Marketing Efficiency Ratio (MER), I talked about zooming out and looking at total revenue against total marketing spend. That’s a great “health check” metric.

But pairing MER with LTV takes it a step further. MER tells you whether your overall marketing is efficient. LTV tells you whether each customer you’re bringing in is worth more than the cost to acquire them.

Together, they give you a much clearer sense of what’s sustainable.

Looking at New vs Repeat Business

Another layer worth adding is splitting out new business from repeat business.

The aim of most businesses is to grow, and that usually means increasing the number of new customers coming in. Repeat business is valuable, often the most profitable, but if you only focus on that, you won’t see whether your ads are helping you grow your customer base.

By splitting the two, you get a clearer picture:

• New business shows whether your marketing spend is bringing in fresh customers.
• Repeat business shows whether your existing customers are staying with you, spending more, and remaining loyal.

For example: I worked with a boutique retailer where repeat customers were making up a large chunk of revenue. That looked great on paper, but when we pulled out just the new customer numbers, growth had stalled. Once we saw that, we adjusted the Google Ads strategy to focus on attracting new customers, while keeping retention strong with email marketing.

This split can also highlight where LTV really shines. For instance, if your average new customer buys three or four times in the first year, that’s where factoring in LTV helps you make confident decisions about how much to invest in acquisition.

Using LTV in Your Ads Strategy

Once you know your LTV, you can:

1. Decide how much you’re willing to pay to acquire a customer. If your average customer is worth £300, you can afford to spend more than you might first think.
2. Focus on higher-value customer segments. If annual subscribers or repeat buyers are more profitable, shape your campaigns to attract more of them.
3. Avoid switching off too soon. Ads might look unprofitable in month one, but if you know the long-term value, you can see past the short-term dip.

A Word of Caution

Of course, LTV isn’t a perfect metric either. It’s based on averages and predictions, and it can vary depending on customer type or seasonality.

But if you’re only looking at the first transaction, you’re definitely not getting the full picture.

I often ask clients: “How much is a customer worth to you?” And many will answer with the first order value. That’s fine for a quick check, but it’s not the real answer.

If your average customer is worth far more over time, and most are, then factoring in LTV is what helps you see the true return on your ads.

Wrapping Up

Customer Lifetime Value isn’t just a buzzword; it’s one of the most practical metrics you can use when managing your own Google Ads.

It helps you:

• Avoid undervaluing your ads.
• Make smarter decisions about the budget.
• Understand where to focus for growth.

If you’re running Google Ads and only looking at the first sale, I’d encourage you to start thinking about LTV. It will give you a truer picture of what your marketing is really delivering.

👉 Book a discovery call with me if you’d like to chat about how to use LTV in your own ads strategy.

And keep an eye out for more posts where I’ll dig into practical ways to calculate and use lifetime value across different types of businesses.