Choosing a Local Model: Size Tiers, Task Matching, and Cost Comparison with Cloud APIs

Choosing a Local Model#

The most expensive mistake in local LLM adoption is running a 70B model for a task that a 3B model handles at 20x the speed for equivalent quality. The second most expensive mistake is running a 3B model on a task that requires 32B-level reasoning and getting garbage output.

Matching model size to task complexity is the core skill. This guide provides a framework grounded in empirical benchmarks, not marketing claims.

Prompt Engineering for Local Models: Presets, Focus Areas, and Differences from Cloud Model Prompting

Prompt Engineering for Local Models#

Prompting a 7B local model is not the same as prompting Claude or GPT-4. Cloud models are overtrained on instruction following, tolerate vague prompts, and self-correct. Small local models need more structure, more constraints, and more explicit formatting instructions. The prompts that work effortlessly on cloud models often produce garbage on local models.

This is not a weakness — it is a design consideration. Local models trade generality for speed and cost. Your prompts must compensate by being more specific.