For Developers
Choosing the Right Model
Match model capabilities to task requirements - 90% of tasks work with smaller models.
5 min readUpdated Feb 1, 2026
Choosing the Right Model
Match model capabilities to task requirements.
The 90/10 Rule
90% of tasks work well with smaller, cheaper models.
Task-Based Selection
const modelMap = {
// Simple tasks → cheap models
classification: 'gpt-3.5-turbo',
extraction: 'gpt-3.5-turbo',
summarization: 'gpt-3.5-turbo',
// Complex tasks → capable models
complex_reasoning: 'gpt-4',
code_generation: 'gpt-4',
creative_writing: 'gpt-4',
};
function getModel(task: keyof typeof modelMap) {
return modelMap[task] || 'gpt-3.5-turbo';
}Cost Comparison
| Model | Input/1K | Output/1K | Speed |
|---|---|---|---|
| GPT-3.5 | $0.0005 | $0.0015 | Fast |
| GPT-4 | $0.03 | $0.06 | Slow |
| Claude Haiku | $0.00025 | $0.00125 | Fast |
GPT-4 is 60x more expensive than GPT-3.5 for input tokens!
Decision Framework
- Start with the cheapest model
- Measure quality on your specific task
- Only upgrade if quality is insufficient
- Consider fine-tuning small models for repeated tasks