Short answer: Define the specific task first, run a structured trial on your own real data with a measurable success criterion, and check three things most buyers skip: whether your data trains their model, whether you can export what you put in, and what happens to the workflow when the tool changes. Feature comparison is the least useful part of the process.
Start with the task, not the category
"We need an AI tool" is not a requirement. "We spend six hours a week extracting details from supplier PDFs into our system, and we want that under one hour with fewer than two percent errors" is. The second version tells you what to trial, how to measure it, and when to stop.
Write the task down before looking at any vendor, including the current time cost, the current error rate and what good would look like. Vendor demos are optimised to reshape your requirements around their product; a written requirement is your defence.
Check whether you need a new tool at all
Two cheaper options first:
- Does your existing stack already do it? Most major business tools shipped AI features in the last two years and a lot of them are unused. Check before buying.
- Would a general-purpose model plus your existing automation platform do it? For extraction, classification and drafting, an API call inside a Make or n8n scenario often outperforms a dedicated vertical tool at a fraction of the cost, with the added benefit that it fits the system you already have.
Run a real trial
Not a demo. A trial on your data, with a pass mark defined in advance:
- Assemble a test set of thirty to fifty real cases, including the awkward ones. Vendors demo on clean examples; your business isn't clean.
- Define the success criterion numerically before you start. Accuracy threshold, time saved, error rate.
- Have someone who isn't the champion run it. The person who found the tool will unconsciously give it easy cases.
- Measure the full workflow, including checking the output. A tool that's fast and requires heavy review may save nothing.
- Test the failure cases. What does it do with a document in the wrong format? Does it fail clearly or produce confident nonsense?
The contractual questions that matter
More consequential than any feature:
- Is your data used for training? Business and enterprise tiers usually exclude it; consumer tiers often don't. Get it in writing.
- Where is data processed and stored? Relevant for UK GDPR transfer obligations. EU or UK processing options simplify your position.
- Is there a data processing agreement? You need one if personal data is involved. No DPA is a hard stop.
- Can you export everything? Including any structure or configuration you build. Test the export during the trial, not at renewal.
- What's the retention and deletion position? How long do they keep your inputs, and can you require deletion?
- Sub-processors? Most AI tools are wrappers over a foundation model provider. You need to know who's in the chain.
The costs that don't appear on the pricing page
- Integration. A tool that doesn't connect to your stack needs a human bridge, which is the cost you were trying to remove.
- Review time. If output needs checking, that's a permanent cost line.
- Training and adoption. Real hours, and the point at which many tools quietly fail.
- Usage-based pricing. Model your realistic volume, not the sales example.
- Switching cost. Assume you'll move within three years and check what that involves.
Frequently asked questions
How long should a trial run?
Two to four weeks — long enough to hit real edge cases, short enough that inertia doesn't decide for you.
Should I buy a vertical tool or build on a general model?
Vertical tools win when the domain logic is genuinely complex and specific. For extraction, classification and drafting, general models plus your automation platform usually win on cost and flexibility.
What's the most common buying mistake?
Buying before defining the task, then reverse-engineering a justification from the tool's features.
We evaluate tools against your architecture, not against feature lists. Get in touch.
