Why This Matters

If you've used any LLM API, you've probably seen a spec sheet listing something like "128K context window" or "1M context window" and assumed bigger automatically means better. It's easy to think of it like storage space — more is always good, right?

Turns out, it's more complicated …

Why This Matters

If you've used the OpenAI or Claude API even once, you've seen the word "tokens" everywhere — in the pricing page, in the error messages ("context length exceeded"), in the response object. For a beginner, this is confusing. Why not just charge per word? Or per API call …