Not every question you ask ChatGPT needs the same amount of horsepower behind it. Drafting a quick email is a different job than debugging a tricky spreadsheet formula or working through a multi-step problem, and ChatGPT lets you choose how much effort goes into each answer.

In the model options, you'll typically see a fast option (often labeled Instant) and one or more advanced reasoning options (often labeled High). Knowing when to use each one can save you time and get you a noticeably better answer on the tasks that need it.

When should I use the fast (Instant) model?

Instant responds in just a few seconds, giving you a quick, direct answer without pausing to reason step by step. It's the right choice for:

• Drafting or rewriting an email.
• Quick summaries of a short document.
• Simple questions with a clear, factual answer.
• A first pass at brainstorming ideas.

When should I use the advanced (High) model?

High mode takes longer — anywhere from several seconds to a minute or more — because it works through the problem step by step before answering. It's worth the wait for:

• Debugging code or troubleshooting a technical issue.
• Reviewing or analyzing a complicated document, like a contract or dataset.
• Multi-step math, logic or planning problems.
• Research or analysis where accuracy matters more than speed.

What if I'm not sure which one to pick?

Leave it on Instant and read the response. If you notice ChatGPT struggling with the task, that's usually your cue to switch to a higher thinking mode.