How We Route Between a Cheap Model and an Expensive One
A working note on llm model routing strategy — what matters, what does not, and where projects usually go sideways.
Somebody asks about llm model routing strategy roughly once a fortnight, usually after a decision has already been half made. Here is the answer we give on the call, written down so you can read it first.
What people are actually asking
When someone raises llm model routing strategy, they normally mean one of three things: is this going to be expensive, is this going to break, or did we already make a mistake.
Worth separating those before the technical discussion starts. They have different answers.
What this looks like in practice
In projects like these the shape repeats. Someone maps the current process, finds three painful steps, and discovers only one of them justifies real engineering.
A team we would typically advise starts with the step generating the most back-and-forth email. Not the most interesting one.
The first version covers the common case and a human handles the rest. That is the design, not a compromise.
Common mistakes
The expensive one is scoping to the edge case. A requirement that affects two percent of users can double the build.
The quiet one is skipping instrumentation, then guessing at causes for a month.
And the recurring one is buying flexibility nobody uses. Every configuration option is a support burden with a delayed invoice.
How we approach it technically
Start with the data model. Most bad decisions here are downstream of a schema that made an assumption nobody revisited.
Then the failure modes. Then the interface. Interfaces are cheap to change; schemas and contracts are not.
Alert on rate of change rather than fixed thresholds. Quiet degradation is the failure that costs customers without waking anyone.
A sequence that tends to work
- Write the outcome and the metric, one sentence each, agreed by whoever signs off.
- Map the process end to end, including the manual steps people are slightly embarrassed about.
- Pick the single highest-friction step and ignore the rest for now.
- Ship a narrow version behind a flag to a handful of real users.
- Watch it for two weeks against the number from step one.
- Expand only where the data says it pays.
Step three is where teams cheat. Keeping it honest turns a six-month project into a six-week one.
What we insist on
One owner. One metric. One rollback plan. Those three cover most of the risk on work like this.
We also write the decision down with the date and the reasoning, because in six weeks somebody will ask why, and "it felt right" is not an answer that survives a board meeting.
Trade-offs worth saying out loud
Speed against flexibility. Cost against control. Managed services against ownership. None of these are free, and pretending otherwise is how a project goes over budget in month three.
Defaults are underrated. So is deleting a requirement.
Things people believe that are not quite true
That more tooling reduces risk. Usually it moves the risk somewhere less visible.
That a rewrite resets the clock. It resets the bugs too, and you get a new set.
That the team will document it afterwards. They will not, unless it is part of the definition of done.
Frequently asked questions
How long does llm model routing strategy usually take?
A narrow first version is normally four to six weeks. Anything quoted at three months with no shippable slice in between is a risk, not a plan.
What is the most common mistake with llm model routing strategy?
Scoping too wide. Covering every case in version one delays feedback and inflates cost with no matching benefit.
Do we need a dedicated team for this?
Not at the start. One owner with a few hours a week plus a small build team is enough until the first version proves value.
How do we know whether it worked?
Pick the number before you build: hours saved, error rate, response time or conversion. Compare a two-week window before and after.
What should we do first?
Write one sentence describing the outcome of llm model routing strategy, then map the workflow it touches. Both take an afternoon and remove most of the guesswork.
Conclusion
The useful move on llm model routing strategy is almost always the smaller one. Ship a narrow slice a real user can touch this month, measure it, then decide what deserves the next four weeks.
Everything gets easier once something is live.
Related reading and next steps
- AI product engineering — how we run this kind of work.
- All Augere Labs services.
- More writing from the team.
Want a second opinion on llm model routing strategy for your setup? Book a 30-minute call. We will say plainly if it is not worth building.
FAQ
Frequently asked questions
How long does llm model routing strategy usually take?+
A narrow first version is normally four to six weeks. Anything quoted at three months with no shippable slice in between is a risk, not a plan.
What is the most common mistake with llm model routing strategy?+
Scoping too wide. Covering every case in version one delays feedback and inflates cost with no matching benefit.
Do we need a dedicated team for this?+
Not at the start. One owner with a few hours a week plus a small build team is enough until the first version proves value.
How do we know whether it worked?+
Pick the number before you build: hours saved, error rate, response time or conversion. Compare a two-week window before and after.
What should we do first?+
Write one sentence describing the outcome of llm model routing strategy, then map the workflow it touches. Both take an afternoon and remove most of the guesswork.
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