Personal Finance
Deciding Whether an AI Tool Is Worth Paying For
By Jim Vernon, Editor, AI Intelligence International · Published 17 March 2026 · Reviewed against our editorial standards · About the author
Twenty pounds a month sounds trivial and is £240 a year, repeated across six tools, indefinitely. The question is not whether a tool is useful — nearly all of them are somewhat useful — but whether it clears the bar its price sets.
This article gives an arithmetic test that takes five minutes and is considerably more reliable than the sense of whether a tool feels worth it.
Key takeaways
- Convert the price into hours: Take the annual cost and divide by your realistic hourly value — for employees, salary divided by working hours; for freelancers, the true rate including unbilled time.
- Count the review time: Time saved is gross; time saved minus time spent checking, correcting and re-prompting is net, and only net counts.
- Value that is not time: Some tools do not save time; they raise a floor.
- The free-tier comparison: The right comparison is almost never the tool against nothing.
Convert the price into hours
Take the annual cost and divide by your realistic hourly value — for employees, salary divided by working hours; for freelancers, the true rate including unbilled time.
A £240-a-year tool for someone worth £25 an hour must save just under ten hours annually, or about fifty minutes a month, to break even.
Stated that way, most decisions become obvious. Fifty minutes a month is a low bar for a tool you use daily and an impossible one for a tool you open twice a quarter.
Count the review time
Time saved is gross; time saved minus time spent checking, correcting and re-prompting is net, and only net counts.
For tasks with cheap verification the two are close. For tasks where you must read the output carefully against a source, net savings are frequently under half of gross.
Measure this once on a real task rather than estimating it. The gap between the estimate and the measurement is usually large and always in the same direction.
Value that is not time
Some tools do not save time; they raise a floor. A tool that makes your worst output acceptable has value even if it makes your best output no better.
Others reduce risk — catching an error before it reaches a client, or a compliance issue before it reaches a regulator. Price those at the expected cost of the mistake, not at the time saved.
A third category enables work you could not otherwise do at all. That is worth whatever the resulting work is worth, and it is the only category where a high price is easy to justify.
The free-tier comparison
The right comparison is almost never the tool against nothing. It is the paid tier against the free tier of the same tool, or against a general assistant you already pay for.
Marginal value is what you are buying. A specialist tool must beat what your existing general tool already does, which is a much higher bar than being useful in isolation.
Run the same real task through both before deciding. Feature lists systematically favour the paid option in ways that use rarely confirms.
Switching and lock-in costs
Count the cost of getting your data out. A tool holding your notes, templates or history has a departure cost that should be part of the entry decision.
Prefer tools with plain-format export. In a category changing this quickly, the ability to leave cheaply is worth a small premium.
Avoid building irreplaceable workflow around any single provider's proprietary features unless the gain is very large.
Reviewing the decision
Diary a check three months after subscribing. Value assessed at signup is a prediction; value assessed after three months is a measurement.
The specific question at review is not whether the tool is good but whether you would buy it again today at the same price knowing what you know.
Cancel on a no. Sunk cost has no bearing and the friction of cancelling is smaller than a further year of fees.
Worked example: three tools assessed
Tool A, a general assistant at £18 a month, used daily. Break-even at a £30 hourly value is about seven hours a year; measured net saving was roughly two hours a month. Clear keep.
Tool B, a specialist writing tool at £29 a month. Gross saving looked good, but review time consumed most of it, and the general assistant already did eighty per cent of the job. Marginal net saving: about twenty minutes a month against a break-even of twelve hours a year. Cancelled.
Tool C, a transcription service at £12 a month, used four times a month for client calls. Net saving about forty minutes per use, so roughly thirty-two hours a year against a break-even under five. Kept, and upgraded.
The pattern held across all three: frequency of use predicted the outcome better than the perceived quality of the tool.
Frequently asked questions
What hourly value should I use if I am salaried?
Annual salary divided by roughly 1,800 working hours gives a usable figure. It understates total employment cost but reflects what an hour is worth to you personally, which is the relevant question for a personal purchase.
How long should I trial a tool before deciding?
Two to four weeks of genuine use. Shorter than that and novelty dominates; longer and the decision tends never to get made.
Is one expensive tool better than several cheap ones?
Usually, because overlap between cheap specialist tools is high and each one carries a switching and attention cost. One capable general tool plus at most one specialist is the common optimum.
Do annual discounts change the maths?
Slightly. A fifteen per cent discount lowers the break-even by fifteen per cent and removes your ability to leave, which in a fast-moving category is often worth more than the saving.