title: if multiple pieces of state data always change together should i only keep one in state and the rest in class vars?
body: <p>having a hard time understanding exactly what to keep in state for plain React.</p>
  
  <p>say i have a top component <code>&lt;App&gt;</code> (holding all state) and a few other display components nested (displaying passed props but have no state)</p>
  
  <p>it seems my app can get on just fine by moving almost all the data to class variables and keeping just a handful in state.</p>
  
  <p>my question is: if multiple pieces of data always change together should i just pick one to keep in state and put the others in class variables since triggering a change in one will re-render the <code>&lt;App&gt;</code> component anyway - including the nested components that are displaying class variables?</p>