Habit Tracking.

I noticed the habit tracker apps for Android, and realized I could do that for free.

With Google Sheets, in a nice, well-designed spreadsheet.  One could even use Data Validation to make a plethora of check boxes instead of manually filling in data.

However, sometimes one might want to enter a data point, instead of just a "check in a box", a data point such as quantity and not a simple Yes or No.  For instance,  I put "N" if I didn't take a walk that day, but if I did walk that day, I want to note vaguely the distance, which I have a convoluted method of measuring circuits completed, rather than a real distance measure.  A "3" entry for me equals a bit more than a mile.

Note that the stand-alone apps aren't particularly expensive, but I could use Sheets for other things, too, and have the capacity to do my own metrics at various points in time.