Don't create objects using the new keyword

If you have a class you want to use in different places and which requires a configuration, don't be tempted do this:

public function index (Request $request)
{
    $transistor = new Transistor(config('settings.key')) ;
    $station = $transistor->getStation();
}

Much better is to bind it in the service provider (e.g. AppServiceProvider):

$this->app->bind(Transistor::class, function() {
    return new Transistor(config( 'settings.key')) ;
);

Once it's bound, you can just inject it in e.g. a method by providing it as an extra method argument with a type-hint:

public function index(Request $request, Transistor $transistor)
{
    $station = $transistor->getStation();
}

It allows you to do fancy things such as setting up the class instances in a different way when you use them in testing:

$this->app->bind(Transistor::class, function() {
    if (App::environment('testing')) {
        return new Transistor(config( 'settings-testing.key')) ;
    }
 
    return new Transistor(config( 'settings.key')) ;
);