To provide the simplest possible implementation and user interface for each request.

I model systems, ranging from basic to very complex, delivering the output that best suits the customer's needs.
For example, a basic system example is why the area of any triangle equals its height times its base divided by two. In this case, the output is a single sheet of paper with a triangle and its enclosing rectangle, which can be further decomposed into two rectangles, each of which has two equal right-angle triangles.
Some examples of very complex systems I have modeled are a program for concrete pavement models design, deterioration and maintenance developed for a World Bank project in the late 90s and now the design of a self-sustainable, small- scale (200 kg per week) green ammonia production, including the modifications needed to be done on internal combustion engines to become ammonia powered.
More pertinent to guru.com is that you state that you need an app that does such and such, and I develop the backend (Kotlin or Swift, can also be java or Objective-C) plus a very simple user interface, although I explicitly state that I am not a user interface design specialist.

Work Terms

It depends on each request, but generally, I try to solve the problem first and then submit a screenshot of the proposed solution. If you like it, payment terms are in accordance with guru.com guidelines.