Which AI Tool Should You Use at Work?

A customer needs an order update. A supplier sends a new quotation. Your sales manager has a spreadsheet to review. AI can help with all three, but you do not need the same tool or setting for each one.

This guide explains the everyday choices inside ChatGPT, Claude, and Gemini, why some tasks use more of your plan, and how to test a tool on work your team already does. No technical background needed.

How to choose an AI model

ChatGPT, Claude, and Gemini are apps. Inside each one are different models that read your request and write the answer, and some offer thinking settings that control how much effort goes into a question. What you see depends on your plan.

In this guide, fast, standard, and stronger describe three levels of work. They are not button names in any specific app.

Fast: rewriting emails, summarizing short messages, turning meeting notes into a checklist. Easy to check, so speed matters most.
Standard: comparing two supplier quotes, reviewing a sales spreadsheet, making sense of several reports.
Stronger: contract terms that disagree, an invoice that does not match the purchase order, a decision with several costs and deadlines. Ask it to show what is uncertain, and have a person check the figures.

Start with the simplest option that gives you an answer you can check. Move up only when the work needs it.

Five everyday tasks to try

Start with something an employee already does, then see whether AI makes it easier.

Writing a supplier follow-up. A buyer needs to chase a late shipment. A fast option can draft the email in seconds.

Try asking: "Write a short supplier follow-up using these confirmed details: [paste details]. Ask for the latest shipping date and tracking number. Do not invent a delivery promise."

Understanding a sales spreadsheet. Upload an approved sales file to a standard option and ask what changed. Check the totals against the original.

Try asking: "Compare sales by product group for these two months. Show which groups increased or decreased, and point out any missing information."

Comparing supplier quotations. One supplier has a lower unit price but higher setup and freight. A stronger option can weigh the full cost, delivery time, and payment terms.

Try asking: "Compare these two quotes, including unit cost, setup, freight, minimum order size, and delivery date. Show the differences and list what we need to confirm before choosing."

Check all prices and promises with the suppliers.

Finding differences in invoices. AI can list mismatches in quantity, price, and fees so an employee knows what to investigate. The AI should not approve payment, and it should not guess that two similar product codes mean the same thing.

Try asking: "Compare these three documents. List what matches, what differs, and what needs a person to review. Show where you found each amount."

Answering order-status questions. AI can draft the reply using the current details you give it. A chat app does not see your ERP, order records, or carrier updates on its own. If your team answers these all day, a connected workflow can check orders and prepare replies for a person to review.

Which model should you choose?

You do not need to memorize every name. Pick a starting point below, and try a stronger option on the same task if the first one misses details.

ChatGPT

Instant is a good start for emails, short summaries, and simple questions. Medium suits comparing quotations or analyzing a sales sheet. High helps with difficult problems across several documents. Some plans also offer Extra High or Pro. More thinking does not guarantee a better answer, so use heavier settings only when you see a benefit.

Claude

Claude Haiku 5.5 is fast for short messages and summaries. Claude Sonnet 5.5 is a strong everyday choice for analysis and writing. Claude Opus 5.5 handles harder work, like complex agreements or conflicting records.

Claude Fable 5.1 is built for especially demanding work and may use more of your allowance or extra usage credits. Claude Mythos 5.1 is a restricted specialist model most distributors and suppliers will not need. Before using Fable or Mythos with confidential files, check your account's data-retention rules. These models normally require at least a 30-day retention period unless Anthropic approves an exception.

Gemini

Gemini Flash-Lite and Flash handle quick everyday work. Gemini Pro is for more detailed analysis, like comparing several supplier quotes. Gemini Argon is a higher tier for demanding tasks on eligible plans. Gemini may also offer Low, Medium, or High thinking. If your company uses Gmail, Docs, and Sheets, check the AI features built in there first.

Keep it simple

Begin with the default or fast option in the app your team already uses. Tools like Codex and Claude Code are for people who build software, so most sales, purchasing, and operations teams can skip them. There is no single best model, only the one your team can access, understand, and check.

Why some tasks use more of your plan

Rewriting a five-line email is far less work than comparing an 80-page catalog with several quotations, even though both are one request. AI measures this work in small units called tokens, the pieces of information it reads and writes. You never need to count them. Long documents, long conversations, and harder questions simply use more of your plan.

A short question can still be a big job. "Find everything wrong with these invoices" may mean reading hundreds of pages, and if the AI also searches your files or uses connected tools, it may need several steps to finish. Detailed token billing mainly matters for companies that pay for AI through a developer connection called an API.

Checking your usage

Claude: Open Settings, then Usage. Eligible paid accounts can show how much of the current allowance has been used and when it resets.
ChatGPT: Check the model picker or the notice that appears when you reach a limit. It may show when that model is available again or offer another option. Not every ChatGPT account has a single usage page showing everything left.
Gemini: On supported personal accounts at gemini.google.com, open Settings, then Usage limits, then Usage. Work and school accounts may look different.

If you reach a limit, check the reset time or switch to another available model before paying for extra usage.

Making your plan last

Use a fast option for straightforward jobs. Share the relevant part of a document instead of a whole folder, ask for short answers when that is enough, and start a fresh conversation for unrelated tasks. Keep the facts needed for a correct answer, and use only company-approved accounts for confidential files.

Try one task with your team

Pick one task your team handles every week and a few examples where you already know the right answer. Use approved or sample information.

Try an easy example. Give a fast option a normal request. Did it use the facts correctly? How much did you need to change?
Try a difficult example. Include a missing product code, conflicting dates, or an unexplained fee. Does the tool flag the problem instead of guessing?
Compare. Try a stronger option only if the simpler one struggled. Note how long checking and correcting each answer takes. The bigger model is only worth it if it makes the work easier or more reliable.

Then agree as a team: what a good answer looks like, which option to use next time, and who approves the result before it affects an order, a customer, or a payment.

A final thought

You do not need to become an AI expert. Start with an everyday task, choose a simple option, and check the results. As your team gets comfortable, take on harder work and decide whether it is worth the extra time or usage.

Sources and further reading

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How to choose an AI model

Five everyday tasks to try

Which model should you choose?

1ChatGPT

2Claude

3Gemini

4Keep it simple