# When not to add infrastructure

> The cheapest, most reliable component is the one you never run.

Concept · Requirements & scale · https://levelcode.org/concepts/when-not-to-add-infrastructure

Every component you add — a cache, a queue, a search cluster, another service — brings an operating cost and new failure modes: it must be deployed, monitored, upgraded, secured, backed up, understood at 3 a.m., and paid for. Good designs add components only when a requirement or a measured bottleneck demands one.

## Questions to ask before adding something

1. **Which requirement fails without it?** If you can't name one, don't add it.
2. **Can an existing component do it?** PostgreSQL covers job queues (`FOR UPDATE SKIP LOCKED`), full-text search, JSON documents, geospatial queries and pub/sub (`LISTEN/NOTIFY`) for modest loads.
3. **What's the failure mode?** A cache that's empty, a queue that's backed up, a search index that's stale — what does the user see?
4. **Who operates it?** A managed service still needs someone who understands it.
5. **What does it cost** at today's scale, and at 10×?

## Common premature additions

| Added | Often unnecessary because |
|---|---|
| Kafka for a few hundred events per second | A database-backed queue or a managed queue is far simpler |
| Microservices for a five-person team | A modular monolith deploys faster with fewer failure modes ([monolith vs microservices](https://levelcode.org/concepts/monolith-vs-microservices)) |
| A cache in front of a fast, lightly loaded database | It adds staleness and invalidation bugs for little gain |
| Sharding at a few hundred gigabytes | One well-indexed primary handles it |
| Elasticsearch for exact lookups | A database index does it |

## Design for change instead

You don't need the component now if you can add it later without a rewrite. Keep interfaces narrow (a `Store` interface the cache can wrap later), choose partition-friendly keys, and write events to an outbox table even before anything consumes them. Then add infrastructure when [capacity estimation](https://levelcode.org/concepts/capacity-estimation) or monitoring says you need it.