The right KPIs at each stage of the customer journey

Measure the journey, not isolated numbers

The most common mistake is tracking numbers without connecting them to the customer's journey. Yet a customer goes through stages: they discover, they try, they come back, they pay, they recommend. Each stage has a question and a KPI. Tracking the journey rather than metrics in bulk lets you pinpoint the leaking stage — and that's almost always where, on one specific link, the biggest growth lever lies.

A simple, famous framework structures this journey: the AARRR model, nicknamed "pirate metrics" (because it sounds like a pirate's cry).

The AARRR model

graph TD
    A[Acquisition<br/>they arrive] --> B[Activation<br/>first good experience]
    B --> C[Retention<br/>they come back]
    C --> D[Revenue<br/>they pay]
    D --> E[Referral<br/>they talk about it]

Acquisition: how people find you. KPI: visitors per channel, cost per channel, organic vs paid traffic.
Activation: the first successful experience. KPI: sign-up rate, activation rate (% who perform the key action — create a project, make a first purchase).
Retention: do they come back? KPI: 7-day / 30-day retention rate, churn rate.
Revenue: how much they bring in. KPI: paid-conversion rate, average order value, MRR (monthly recurring revenue).
Referral: do they talk about it? KPI: referral rate, NPS (Net Promoter Score), viral coefficient.

The value of this framework: it forces you to ask, for each stage, "am I measuring it, and is it healthy?". An unmeasured stage is a blind spot.

The four KPIs that decide profitability

Beyond the journey, four indicators govern the economic viability of almost any business. Understanding them is non-negotiable.

CAC (Customer Acquisition Cost): what you spend on average to win a customer. Calculation: marketing and sales spend over a period ÷ number of new customers over that period.
LTV (Lifetime Value): how much a customer brings in on average over their entire lifespan. For a subscription: average monthly revenue × average lifespan in months.
The LTV / CAC ratio: the arbiter. A healthy ratio is generally at least 3 to 1 (a customer brings in three times what it costs to acquire them). Below 1, you lose money on every customer won — accelerating only accelerates the losses.
CAC payback time: how many months it takes a customer to repay their acquisition cost. The shorter, the less growth weighs on cash flow.

Growing with an LTV/CAC below 1 is pressing the accelerator of a car with no wheels: you burn fuel and go nowhere.

Churn: the silent killer

For any subscription or recurring-revenue business, the churn rate deserves particular attention, because its effect is insidious. A monthly churn of 5% seems harmless, but it means that in a year you lose more than half your base — you have to run just to stay in place. Measuring churn, understanding why customers leave (via the recordings and surveys in chapter 3), and reducing that number often has more impact on growth than acquiring more.

Adapt KPIs to your model

Not all KPIs matter to everyone. A blog monetized by ads watches traffic and reading time. An e-commerce watches conversion rate, average order value, and return rate. A SaaS watches MRR, activation, and churn. A service business watches the quote-conversion rate and margin per engagement.

The right approach isn't to copy someone else's KPI list, but to start from your customer journey (the AARRR stages applied to your case) and choose, for each stage, the indicator that reveals whether it's healthy.

The discipline of the North Star Metric

Many high-performing companies choose a North Star Metric: a single indicator that sums up the real value delivered to customers, and that the whole team (even a solo one) keeps in mind. For a storage service, it would be files actually accessed; for a marketplace, successful transactions; for a media outlet, engaged reading time. This compass-metric prevents scattering and aligns all decisions on what truly creates value — not the vanity metric of the day.