"LTV needs to be at least 3 times CAC" is probably the most repeated benchmark in startups. It's a decent starting point, but applying it the same way to a B2B SaaS, a lending fintech, and an e-commerce store hides more than it reveals — each vertical has one metric that breaks the business before the others, and it isn't the same across all five.
In SaaS, growing MRR (Monthly Recurring Revenue) with NRR (Net Revenue Retention) below 100% isn't growth — it's replacing departing customers with new ones, at an ever-rising cost. An NRR of 115% means the existing customer base, without adding a single new one, already generates 15% more revenue than the prior year through upsell and expansion.
The metric that breaks a SaaS fastest is monthly churn: at 5% monthly churn you lose 46% of your base in a year, versus 21.5% at 2%. The difference between those two scenarios defines whether the business can scale or is running on a treadmill.
See also: NRR · Churn Rate · SaaS landing
In Fintech, ARPU and gross margin can look healthy on paper and fall apart once you deduct fraud and default. The real loss isn't fraud + default added up simultaneously — you have to subtract the overlap between them — but even corrected, 1.2% fraud and 3.5% default on $1M in transaction volume is nearly $47,000 a month vanishing from margin.
The metric to watch here is effective post-risk margin, not nominal P&L margin. A business with 65% nominal margin can have a real margin of 62% once risk is deducted — the gap looks small, but at scale it's hundreds of thousands of dollars a year.
See also: Fraud Rate · Default Rate · Fintech landing
In E-commerce, the most-cited metric — GMV (Gross Merchandise Value) — is also the one that says the least about whether the business makes money. Net Contribution Margin, which deducts product cost, logistics, and returns, is the number that actually matters. A 25% return rate combined with 12% logistics cost can turn a 45% gross margin into a negative net contribution margin if the average order value is low.
See also: AOV · E-commerce landing
In Proptech, a building can be "full" (high physical occupancy) and still lose money if the collection rate is low. Economic occupancy (physical × collection) is what defines real revenue against GPR (Gross Potential Rent) — the gap between the two is the most underrated improvement lever in the sector.
See also: Physical Occupancy · Proptech landing
In Edtech, the number one risk isn't churn — it's overestimating enrollment volume when deciding to produce a course. A course with $20,000 in production cost, estimated for 800 students, has an amortized cost of $25 per student; if only 200 show up, that cost jumps to $100 — more than many B2C courses charge in full monthly ARPU.
See also: Completion Rate · Edtech landing
LTV:CAC > 3x is still a reasonable starting point in almost every case. But the metric that will break your business first — churn in SaaS, risk in Fintech, returns in E-commerce, collections in Proptech, volume in Edtech — is different in each vertical, and no generic benchmark replaces it.
The Unit Economics Calculator adapts its questions, formulas, and benchmarks to your specific vertical — pick yours and get the full diagnosis in 3 minutes, free.
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