AI Guides › Playbooks
By Nigel Guy · 5 min read
Someone shares a single site that supposedly does images, video, documents and conversions, free, no limits. You try it once, it works, and you build a habit or a client workflow on it. It feels fine right up to the moment the limit appears, usually mid-job, usually on the file that mattered.
The rule: never rely on a free tool until you have deliberately hit its limit on purpose, with a throwaway file, and written down what happened.
Free tiers are acquisition costs. The provider pays for compute every time you press the button, so the free allowance is sized to let you feel the product and then meet a boundary. Official pages say as much. OpenAI's help centre for the ChatGPT free tier says the default model and available limits "can change over time", and that while everyday text chat is unlimited subject to abuse-prevention safeguards, file uploads, image generation, voice and data analysis have separate usage limits. Adobe's generative credits FAQ says that on free plans credits are allocated on first use of a Firefly feature and expire one month later. So even the big names have limits; they just state them. The sites that say "no limits" are usually the ones that have not stated theirs.
Run this once per tool, in about five minutes, before it touches real work. Copy the card into a note.
| Check | What you do | What you write down |
|---|---|---|
| 1. Terms | Open the pricing page and the terms. Search for "fair use", "credits", "daily", "watermark", "commercial". | The exact wording of any cap or restriction, or "none stated" |
| 2. Wall | Run the same small job repeatedly with a throwaway input until something changes. | How many runs, and what changed: block, queue, lower quality, watermark, sign-up prompt |
| 3. Output | Download one result. Check size, resolution, file type, watermark. | Whether the free output is usable as it stands |
| 4. Exit | Look for export, delete-my-data and account-deletion options. | Whether you can leave with your work |
| 5. Data | Read what the privacy policy says about uploads. | Whether you may upload client or personal material at all |
Checks 1 and 5 are reading, not testing. Do them first, because they can end the test in under a minute.
The wall is rarely a polite message. Common shapes: a quiet drop in quality, a queue that gets longer, a watermark that appears from the Nth export, a "sign in to continue" prompt, or a cap that resets on a timer you were not told about. Note which one you hit and when it reset, if it did. ChatGPT, for example, shows a notice when you reach a tool limit and shows the reset timing in the product, which is the behaviour you want to see from any tool.
Free usually means you are paying with something other than money: attention, data, or both. Before you upload anything containing other people's details, read the privacy policy for what happens to uploads. If you handle personal data in the UK, the ICO publishes guidance on AI and data protection aimed at organisations; it is the right place to start if a free tool would touch customer or client information. A free converter is not an exception to your obligations.
Say you freelance and a friend recommends "SiteX", a free site that resizes images, removes backgrounds and converts PDFs. SiteX is invented for this example.
Verdict: fine for personal one-offs, not for client work, and you now know the exact job where it fails. That is a result, not a disappointment.
| Result | Decision |
|---|---|
| Wall is high, output usable, data terms acceptable | Use it, and re-run the card whenever the site changes |
| Wall is low or soft but output is fine | Use it only for low-stakes jobs, with a named backup |
| Output unusable, data terms unacceptable, or no exit | Drop it for anything that matters |
Always name a backup tool before you depend on a free one. A paid tier of the same product is also a backup, but check the £ price at checkout, because many providers price in dollars and the sterling figure moves with exchange rates and VAT.