Which AI Model to Use for Which Job? A Practical Guide
Not sure which AI model to use? Match the model to the task: fast small models, strong reasoning models, or local models, with simple rules of thumb.
AI privacy made practical: what never to paste into a chatbot, how to anonymize documents, which settings to check, and when a local model makes sense.
To share data with AI safely, assume anything you paste could be stored and possibly reviewed, then share only what the task truly needs. Remove names, numbers, and secrets before you paste, check your account’s data settings, and use a local model when the information should never leave your computer. That covers most of the risk with very little extra effort.
This guide walks through each step in plain terms. It’s practical advice, not legal advice. If you handle regulated data at work, follow your organization’s policies first.
When you type into an AI assistant, your text usually travels to the provider’s servers to be processed. Depending on the service and your settings, conversations may be kept for some time, used to improve models, or reviewed for safety. Policies differ between providers and between free, paid, and business plans.
None of that makes AI tools unsafe to use. It just means a chat box is not a private notebook. Treat it like sending an email to a company you trust, but not one you’d hand your passwords to.
Some information is almost never needed to get a good answer, and it causes real harm if it leaks.
A useful test: would you be comfortable if this exact text appeared in a support ticket at the AI company? If not, edit it first.
Most tasks work just as well with placeholders. The AI doesn’t need to know your client is called Maria Lopez to fix the tone of an email to her.
Replace real details with consistent labels, then put them back afterwards.
Before:
Rewrite this: "Hi Maria, your invoice #48213 for Lopez Dental
is overdue. Please pay to account 0042-7781."
After:
Rewrite this: "Hi [CLIENT], your invoice [INVOICE_ID] for
[COMPANY] is overdue. Please pay to [ACCOUNT]."
For spreadsheets and databases, the AI usually needs the structure, not the rows. Share column names and two or three made-up example rows instead of the whole file. You’ll still get a working formula or script.
If you need advice on a sensitive situation, describe it in general terms. “A long-time supplier missed two deliveries and I want to renegotiate” is enough for useful help. The full email thread isn’t.
Documents and images can carry more than you see: tracked changes, comments, file metadata, or location data in photos. Export a clean copy or take a screenshot of only the part you need.
Every major AI service offers some controls, though names and locations change over time. Look for these in your account settings:
Read the provider’s privacy page for the specifics. Don’t rely on assumptions, including ours, about how a particular service handles your data.
Not every task needs the same level of caution. Match the tool to the data.
| Data sensitivity | Examples | Reasonable approach |
|---|---|---|
| Public | Rewriting a blog post, explaining a concept | Any reputable assistant |
| Personal but low-risk | Planning a trip, drafting a personal email | Mainstream assistant, with placeholders for names |
| Confidential | Client details, internal plans | Approved work account, anonymized text |
| Highly sensitive | Health records, IDs, secrets | Don’t share, or use a local model only |
Local models run entirely on your own machine. Your text never leaves it, which makes them a strong option for sensitive drafts, private notes, or work data you can’t send to a cloud service.
Tools like Ollama make this approachable: you download an open-weight model and chat with it offline. The trade-offs are real, though. Local models need a reasonably capable computer, they’re often slower, and smaller ones are less capable than the biggest cloud models. Our guides on running AI models locally with Ollama and local vs cloud AI models go into the details.
Some tools let you mix both. In BotQuarters, for example, teammates can run on local models through Ollama, and your projects stay on your Mac.
AI agents don’t just read what you paste. They can open files, run commands, and connect to other services. That makes privacy and permissions part of the same question.
We cover this in depth in AI agent security and permissions.
Before pasting anything, run through these four questions:
It takes ten seconds and becomes a habit fast.
It depends on the information and the service. Low-risk details are generally fine, but avoid passwords, financial and ID numbers, health records, and other people’s private data. Use placeholders where you can and check the provider’s privacy settings.
Some do by default on certain plans, and many let you opt out. Policies vary between providers and between consumer and business accounts. Check the data or privacy section of your account settings and the provider’s privacy page.
Replace names, companies, account numbers, and addresses with consistent placeholders like [CLIENT] or [ACCOUNT]. Remove comments, tracked changes, and metadata by exporting a clean copy. After the AI responds, swap the real details back in yourself.
A model running on your own computer processes your text locally, so it isn’t sent to an AI provider. Your privacy then depends on your own device’s security and on any other tools you connect to it. They’re a strong choice for sensitive work, with trade-offs in speed and capability.
Not sure which AI model to use? Match the model to the task: fast small models, strong reasoning models, or local models, with simple rules of thumb.
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