The first version of Groat had eleven categories and a screen for correcting them. In testing, people spent longer fixing the categories than looking at their money.
What we kept
Four groups, chosen by Groat, that answer one question: where did it go. You cannot rename them, merge them or add a fifth.
What we lost
Precision. A coffee bought in a supermarket counts as groceries. Nobody in the beta asked for it back.
The rule we use now
If a feature gives the user a job, it has to save them a bigger one.
