I continue to be impressed by Gemini 3 and it’s become my default agent. It writes in simpler language than ChatGPT (almost as eloquent as Claude), has much larger limits, and, of course, is unbeaten at generating images.

The Gemini app has 3 modes: Fast, Thinking, and Pro. Here’s when to use each:

  1. Simple task, e.g., grammar check, translate, summarize, or basic question? Use Fast. Pro overthinks.
  2. Multi-step logic, e.g., planning a trip with constraints, checking 15 emails, or identifying a subtle error in code? Use Thinking. Flash-based thinking beats Pro.
  3. Large input, e.g. 300-page PDF, 2 hours of video, etc.? Use Pro. It uses the 1M+ token window well.
  4. Complex problem, e.g. PhD-level science or a legal contract review, with high stakes? Use Pro.

If you hit your Pro limit (which is pretty high!), just switch to Thinking, which is smart enough for most jobs anyway.

Source: Gemini