For a single workflow automation with off-the-shelf tools: 2-4 weeks. For a custom AI system built for your specific process: 60-90 days to first measurable results. For enterprise-wide AI transformation: 6-18 months. The most common mistake is trying to do everything at once. Companies that succeed with AI start with one high-pain workflow, prove ROI in 90 days, then expand. Companies that fail try to deploy AI across 10 departments simultaneously and end up with 10 half-finished pilots. Start narrow. Go deep. Expand after proof.