Every AI project takes longer than the initial estimate. Here are honest timelines from dozens of production deployments.
Simple Chatbot (FAQ/Support)
- Quoted: 1–2 weeks
- Actual: 2–4 weeks
- Why it takes longer: the chatbot works in demo. Then edge cases appear. Customers ask questions nobody predicted. The knowledge base needs restructuring. Integration with the existing helpdesk takes a week by itself
RAG System (Document Q&A)
- Quoted: 2–4 weeks
- Actual: 4–8 weeks
- Why it takes longer: document parsing is the bottleneck. PDFs with tables, images, and mixed formatting break every parser. Chunking strategy requires experimentation. Retrieval accuracy needs tuning. The difference between “it works on 5 test docs” and “it works on 5,000 production docs” is enormous
Data Pipeline Automation
- Quoted: 1–3 weeks
- Actual: 2–5 weeks
- Why it takes longer: data quality issues. The source data is messier than anyone admits. Error handling for edge cases. Rate limits on APIs. The “last 5%” of data that doesn’t fit the pattern
Custom Fine-Tuned Model
- Quoted: 4–8 weeks
- Actual: 8–16 weeks
- Why it takes longer: training data preparation takes 50% of the total time. Multiple training runs to get quality right. Evaluation requires domain expertise. Deployment infrastructure needs building
Why Estimates Are Always Wrong
- The demo works on curated data. Production data is messy
- Integration with existing systems always has surprises
- Stakeholder feedback changes requirements mid-project
- LLM behavior is non-deterministic — edge cases emerge over time
My rule: take the quoted timeline and multiply by 1.5–2x. That’s the realistic timeline. If someone quotes you 1 week for a RAG system, they either haven’t built one before or they’re not including integration and testing.