Every Plan CD app is paid for once. There is no subscription, no renewal, no “pro tier” that expires, and no feature that stops working next month unless you pay again. You buy the app, it is yours, and it keeps working for as long as your phone can run it.
That is unusual enough in the current App Store that it deserves an explanation, including the honest bit about what it costs us.
The apps are tools, not services
A subscription makes sense when there is an ongoing cost to serve you: servers, data feeds, storage, support staff, content that is renewed. A subscription is the price of keeping the lights on.
Our apps have no lights to keep on. There is no backend, no account, no sync service and no data feed. The calculation happens on your phone, against figures that are built into the app. Once you have downloaded it, we spend nothing per user per month, and it would be dishonest to charge as though we did.
It also answers a question people rightly ask of a subscription: what happens if the company goes away? For a Plan CD app the answer is nothing. It carries on working exactly as it did the day before. There is no server to switch off.
What “own it” means in practice
Updates are free. When an app is improved, or when the standard it is built on is amended and the figures change, the update comes through the App Store at no cost. Several of the apps have been through complete rewrites since they first shipped, and every one of those went out as an ordinary free update to the same app.
Nothing is held back. There is no artificial ceiling on how many calculations you can do, how many you can save, or how many you can export. A paid app that then rations its own features is a subscription wearing a disguise.
You can stop using it without a chore. No cancellation flow, no “are you sure”, no renewal you forgot about. Delete it and that is the end of the relationship.
The one exception, and why it is still one payment
Legionella Logger is free to download, and a single payment unlocks unlimited properties and an unwatermarked PDF log. That is a different shape from the other apps, and it exists for a specific reason.
The other apps are calculators: you open them, get an answer and close them. The Logger is a record you keep for years, and the value of a record-keeping tool is only clear once you have kept records in it for a few months. A landlord with one property should be able to run the whole monitoring routine, timers, thresholds and all, before deciding whether the paid version is worth it for the rest of the portfolio. So the free tier is the full product for one property, not a demo.
But the unlock is a single purchase. It does not renew. We considered a subscription for it, because it would be the conventional choice for a recurring-use app, and rejected it for the same reason as everywhere else: the app has no ongoing cost to us, and a landlord’s water hygiene log should not stop being exportable because a card expired.
What it costs us
Being straight about the trade-offs:
Every sale has to be earned. There is no recurring revenue to smooth out a quiet month. A slow season for stove installations is a slow season for us. That is fine in a portfolio of several apps with different seasons, and it is the main reason there is a portfolio rather than one app.
No free trial for the paid apps. The App Store does not offer trials for paid-up-front apps. What you get instead is the app page, the screenshots, and these guides, which explain what the app calculates and how, so you can judge before you buy. If you buy one and it does not do what you needed, Apple’s refund process applies and we will not argue with it.
Big improvements are funded by new sales, not existing ones. When an app is rewritten from scratch, as several have been, existing owners get the rewrite for free. That is a cost we choose to carry because the alternative, charging again for the same app, breaks the promise in the title of this article.
We cannot fund the apps with your attention. No ads means no ad revenue. It also means a calculator screen that is just the calculator.
Why this is the right shape for trade tools
The people using these apps are working. An electrician sizing a cable, a landlord logging a temperature, a joiner checking a pitch: none of them wants a monthly relationship with a calculator, and none of them should have to wonder whether the tool will still open on site next year. A tool you own is a tool you can rely on, put in a van and forget about until it is needed.
That is the whole idea. Buy it once, and it is yours.
The fine print
Prices are set per app on the App Store page and can change over time, as they do for anything. What does not change is the model: one payment, no renewals, free updates, no ads, no tracking. Our privacy position is the other half of the same promise.