I legitimately have an idea for an app that solves this problem. Its key feature, besides being open source, would be that people without uteruses could use it too, making any data conceivably collected useless.
I don’t have the skills to make it myself (yet), but if any developer wants to talk I’ll give the idea away. I just want it to be made.
App would be open source, all data local. Perhaps the option to sync to encrypted iCloud or Android equivalent, but certainly not a cloud-based option you need a new login for. All the features currently in these kinds of apps and that make them useful for menstruating people. Now replace “period” with “hair cut”. Non-menstruating people can now use it, earnestly, for tracking when their last hair cut was, making it useful and the data (if it were to be collected somehow) just noise.
I even have a name in mind: “hair**.**cuts” (heavy emphasis on the period in the name.) Idea is that anyone with it on their device has plausible deniability that they are using it for period tracking, but the “period” in the name is an implicit wink so we all know what it’s really being used for.
That is pretty cool. But I have to think since the US is the country in which this is pertinent an iOS app would be most effective.