Here's the truth most vendors won't tell you: you probably don't need to train an AI model at all.

Training vs RAG vs Fine-tuning

ApproachHow It WorksTimeCost
RAG (recommended)AI reads your docs in real-timeDays¥200k-500k
Fine-tuningAdapt existing model2-4 weeks¥500k-2M
Full trainingBuild new model2-6 months¥10M+

Why Most Businesses Use RAG

RAG (Retrieval-Augmented Generation) is the modern approach:

  • No training needed: AI accesses your knowledge base
  • Instant updates: Add docs, AI knows immediately
  • Cheaper: No compute costs for training
  • Faster: Implement in days, not weeks
  • Transparent: You can see what docs AI used

When You Need Fine-tuning

Fine-tuning makes sense when:

  • Off-the-shelf models consistently fail your task (>30% error)
  • You need specific output formats always
  • Performance on your specific data is critical
  • You have quality training data available

Fine-tuning Timeline

  1. Data preparation: 1-2 weeks (collect, clean, format examples)
  2. Fine-tuning: 3-7 days (compute time)
  3. Evaluation: 3-5 days (test, compare to baseline)
  4. Iteration: 1-2 weeks (if first attempt isn't good enough)
  5. Total: 2-4 weeks typical

When Full Training Is Needed

Full training (not fine-tuning) when:

  • Building a competitive advantage product
  • Domain is completely different from existing models
  • You have massive proprietary data (millions of examples)
  • Data privacy requires local-only model

This is rare for typical businesses.

Training Timeline Details

PhaseDurationRequirements
Data collection2-4 weeksDomain experts
Data cleaning1-3 weeksData engineers
Training1-4 weeksGPU compute
Evaluation1-2 weeksTesting framework
Deployment1 weekDevOps

Data Requirements

How much data you need:

  • Fine-tuning: 100-10,000 examples minimum
  • Full training: Millions of examples
  • Quality matters: Bad data = bad model

Greene Solutions Approach

We recommend the simplest approach that works:

  1. Start with RAG—no training needed
  2. If that fails, try prompt engineering
  3. If that fails, consider fine-tuning
  4. Full training only if absolutely necessary

Not sure if you need training?

We'll assess your use case and recommend the right approach.

Book Free Assessment →