Add note about models

Author: DanWahlin

01-setup-and-first-steps/README.md

@@ -451,9 +451,11 @@ Copilot CLI supports multiple AI models from OpenAI, Anthropic, Google, and othe
 copilot
 > /model
 
-# Shows available models and lets you pick one
+# Shows available models and lets you pick one. Select Sonnet 4.5.
 ```
 
+> 💡 **Tip**: Some models cost more "premium requests" than others. Models marked **1x** (like Claude Sonnet 4.5) are a great default. They're capable and efficient. Higher-multiplier models use your premium request quota faster, so save those for when you really need them.
+
 </details>
 
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