Most people will never pick Haiku by name, but cheaper, faster models are why the AI in your apps keeps getting snappier, and Max users now get credits to build their own tools. And the leapfrog game continues. OpenAI just announced GPT-6 within ChatGPT Chat. The average user may not care or even notice. Those who go a bit deeper, code, or do more intensive projects probably will notice.
Of course, I wasn’t sure whether to switch models. My usual recommendation is not to change a model “mid-session,” since the new model may need time to catch up. So, if you do change your model, do it at the beginning of a new session with the appropriate context.
As part of my usual process, I went to Gemini (my “neutral” 3rd party) to ask whether and why I should change models (I’m currently using Sonnet 5.5 medium for my building work). Gemini said I shouldn’t change, so I’m sticking with Sonnet and only using Haiku 5.5 for sub-agent operations, rapid prototyping, or as a fallback if I max out.