How do you properly define and consistently use breakpoints, meaning specific screen width thresholds, to properly organize your app's own overall responsive layout logic in a genuinely clean, maintainable way?

Defining a genuinely clear, consistent set of breakpoints, such as considering anything below six hundred logical pixels wide as a phone, anything between six hundred and nine hundred as a tablet, and anything above nine hundred as a genuine desktop layout, and centralizing these particular threshold values within one single shared utility class or a dedicated set of constants, ensures your entire app consistently makes exactly the same genuinely responsive layout decisions everywhere throughout the codebase, rather than having several separate different widgets each independently hardcoding their own genuinely slightly inconsistent specific threshold values.

class Breakpoints {
  static const double tablet = 600;
  static const double desktop = 900;
}

final isTablet = MediaQuery.of(context).size.width >= Breakpoints.tablet;