The rise of generative AI has raised hopes that high-quality, personalised financial advice might finally become cheap and universally accessible. This column develops a method to quantify the impact of following AI financial advice over a lifetime. The authors find that on the decisions that matter most for long-run wealth, such as investing in diversified equity or building a savings buffer, today’s leading models give advice broadly consistent with what economists would prescribe. But what people get from AI depends as much on the model's ability as on how they write their prompts, with the advice varying by gender, financial literacy, and prior AI experience.