The AI Models Index tracks how frequently and effectively new AI models are...

https://fair-wiki.win/index.php/Is_GPT-5.2_More_Expensive_Than_GPT-5.1%3F_A_Data-Driven_Look_at_AI_Model_Pricing_Trends

The AI Models Index tracks how frequently and effectively new AI models are released, showing there’s a new version about every 4.5 days. While 56% of updates bring improvements, 16% actually cause regressions. On average, models gain +9