Which customer is costing you money? (two customers, same $29 plan)
Last time was caching, and how it can quietly cost more than it saves. Today’s question is a step away from my original itch. I started out asking which feature spent my money. If you sell an AI product, the question that matters more is which customer.
On the demo workspace I use for screenshots, two customers are on the same $29 plan. One costs $3.10 a month in AI calls. The other costs $61.20.
Average them and each one costs $32.15, a bit over the $29 they pay. Looking at that average, you’d decide your pricing is broken and raise it for everyone.
Per customer it looks different. One makes you about $26 a month and the other costs you about $32. Your pricing works for almost everyone. You have one account to talk to, rate-limit, or move to a usage tier.
(This is where a business person would say “unit economics”. I nodded along to that phrase for a while before I looked it up. For an AI product it comes down to one question: does each customer pay more than they cost you?)
AI usage isn’t spread evenly. A few heavy users can carry most of the cost, and a total per model can’t tell you who they are. The only way I’ve found to see it is to tag every AI request with an opaque customer ID and add the cost up per account.
So, the answer: the one costing $61, and an average won’t show you which one that is.
If you run an AI SaaS, how do you handle the heavy user today: a usage cap, a higher tier, or just eating it?
Replies
I chose to make the heavy user impossible by design rather than find them afterwards. My app sells credits, not unlimited use: every song costs a fixed number of credits, the price of a credit is pinned to one dollar anchor on the server, and the subscription refills a set amount each week. On top of that there is a daily cap on songs. So a subscriber who goes wild spends their week's credits and then waits or buys more, and the cost per song stays inside the price. The trade off is that "unlimited" sells better on a paywall. But with a generation that costs real money per call, a plan without a ceiling is a plan where your best fan is your biggest loss.