When you set someone up, Checkup asks when they last had each checkup. Many people can’t remember. That’s normal, and Checkup is built for it.
Unknown isn’t overdue
A lot of apps would treat a blank as “never”, then fill your screen with red overdue warnings. That’s not true, it’s not useful, and it teaches you to ignore the app.
In Checkup, “Not sure” is kept as exactly that: unknown. Those checkups sit under “Not sure yet” on Home, never under “Needs attention”.
A rough answer is enough
You don’t need a date. “Last 6 months”, “6 to 12 months ago”, “1 to 2 years ago” and “over 2 years” are all answers Checkup can work with. It works out a likely due date from the range and says it’s an estimate.
The first real visit fixes it
When you log a visit, that date wins over any estimate. From then on, Checkup knows.