These are the terms for Daily Scales: the app, this website and the YouTube channel. They are short because there is not much to say.
The app
Daily Scales is a free download from the App Store, and all of it runs for seven days from the day you start the free trial. After that it stays closed until you unlock it with a single purchase, made inside the app through the App Store. Nothing is charged unless you choose to buy. If you bought Daily Scales while it was a paid download, it is yours with nothing more to pay. Apple's standard licence terms for App Store apps apply to it. There is no subscription, no account and no service behind it, so once it is unlocked there is nothing that can lapse or be switched off.
The scales, arpeggios, patterns and fingerings it engraves are yours to practise, teach from and print for your own students. Please do not resell them or repackage them as a product of your own.
This website
This site is free to read and collects nothing, as the privacy page explains. Its engravings and text are mine; the same rule applies as for the app: use them for practice and teaching, not for resale.
The YouTube channel
The videos on the Daily Scales channel are made with the app's own engine and published by a tool I wrote that uses YouTube API Services. I am its only user, and I use it only to manage my own channel. In using it, I agree to be bound by the YouTube Terms of Service, and its handling of data is described on the privacy page. Watching the channel is covered by YouTube's own terms.
What it is built on
Daily Scales stands on openly licensed work: the Verovio engraving library, the Literata, Petaluma Script and Bravura typefaces, the JJazzLab SoundFont (CC BY 4.0) and the Versilian Community Sample Library (CC0). Full credits are in the app, and every video's description names the sounds it uses.
Changes and questions
If these terms change, this page will say so plainly. Questions: support@dailyscales.com.