Define “Good” With 4 Numbers
Define “Good” With 4 Numbers
The simplest habit that makes engineering calmer
Most engineering debates are not about code.
They’re about undefined expectations.
“This feels slow.”
“This is not reliable.”
“This is too expensive.”
“This isn’t scalable.”
The problem is not disagreement.
The problem is that nobody defined what “good” actually means.
Over time, I’ve started doing something simple before building anything meaningful:
We define four numbers.
Not twenty metrics.
Not vague goals.
Just four numbers that align engineering, product, and leadership.
1. Latency Target
What should this feel like for a normal user?
Not what is technically possible.
Not what is “acceptable in theory.”
What should the experience actually feel like?
If you do not define this early, you end up optimizing randomly.
Is 800ms fine?
Is 300ms expected?
Does this flow need sub-100ms?
When we define the latency expectation upfront, architecture decisions become easier:
Caching becomes intentional
Query design becomes thoughtful
External dependencies are evaluated more critically
Performance stops being reactive.
2. Error Budget
How much failure is acceptable before we stop shipping and stabilize?
No system has zero errors.
But very few teams define how much instability is tolerable.
An error budget forces discipline.
If we exceed it:
Feature velocity slows
Reliability becomes priority
Root causes are addressed
This prevents the slow decay where teams keep adding features while the foundation quietly weakens.
It shifts reliability from emotional debate to measurable accountability.
3. Cost Guardrail
How much are we willing to spend to support this system?
Cloud costs do not spike because engineers are careless.
They spike because there was no boundary.
If cost is not part of the design discussion:
Overprovisioning becomes normal
Staging runs 24/7 unnecessarily
Dependencies multiply without scrutiny
A cost guardrail does not limit ambition.
It forces smart architecture:
Right-sizing infrastructure
Efficient data storage
Intentional caching
Eliminating waste
Engineering decisions improve when cost is visible.
4. On-Call Expectation
How often is it acceptable to wake someone up?
This number changes behavior dramatically.
If the expectation is:
“Rarely” → systems get more redundancy
“Never for minor issues” → alert quality improves
“Only for user-impacting failures” → noise gets removed
Without defining this, teams slowly normalize chaos.
And chaos eventually leads to burnout.
Why These Four Numbers Matter
When these four are written down, something powerful happens:
Trade-offs become obvious
Discussions become objective
Priorities stabilize
Quality becomes measurable
Instead of arguing whether something is “good,”
you ask:
Does it meet our defined numbers?
If yes, ship.
If not, improve.
Calm engineering is not accidental.
It is structured.
The Real Shift
Many teams optimize for:
Speed
Features
Architecture elegance
Fewer teams optimize for:
Clarity
Guardrails
Sustainability
The best systems I’ve worked on were not the most complex.
They were the ones where expectations were explicit.
If You Do One Thing
Before your next major feature or service, define:
A latency target
An error budget
A cost guardrail
An on-call expectation
Put those four numbers in writing.
Everything else becomes easier.
Closing Thought
Engineering feels chaotic when “good” is undefined.
It feels disciplined when “good” is measurable.
What is one number your current project absolutely needs to define?
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Written by Sharath Chandra Odepalli

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