Do I have to check if user is logged in on every page? (Flutter Firebase Provider)

I’m using Firebase and Provider on my SignIn/Signup part of my mobile app.
Please take a look at the snipets to get a better idea.

main.dart
…

  @override
  Widget build(BuildContext context) {
   return MultiProvider(
     providers: [
       Provider<FirebaseBridge>(
         create: (_) => FirebaseBridge(),),
           StreamProvider(
             create: (context) =>
               context.read<FirebaseBridge>().monitorAuthStateChanges,
                 initialData: null),
     ],
     child: MaterialApp(
     home: const SplashScreen(),
    ...
  ),);}

…

Splash redirects to AuthCheck.

auth_check.dart
…

    class AuthCheck extends StatelessWidget {
      const AuthCheck({Key? key}) : super(key: key);
      @override
      Widget build(BuildContext context) {
        final userModel = Provider.of<UserModel?>(context);
        if (userModel == null) {
          return const WelcomeScreen();
        } else {
          return const Home();
}}}

…

Welcome has buttons to SignIn and SignUp.
SignIn calls FirebaseAuth signInUserWithEmailAndPassword and everything works fine.

SignIn Screen

  void doLogIn(String email, String password) {
context
    .read<FirebaseBridge>()
    .logIn(
      emailController.text.trim(),
      passwordController.text.trim())
    .then(
  (value) {
    Navigator.pushReplacement(
        context, MaterialPageRoute(builder: (_) => const Home()));
    emailController.clear();
    passwordController.clear();
  },
  onError: (error) {
    DialogBoxes.showErrorBox(context,
        message:
            'Ops! Some message and show the n($error)');
  },
);

}
…

And the class that interacts with Firebase.
…

class FirebaseBridge {
  final FirebaseAuth _fireAuth = FirebaseAuth.instance;
  Stream<UserModel?> get monitorAuthStateChanges {
    return _fireAuth.authStateChanges().map(_userModelFromFirebase);
  }
  UserModel? _userModelFromFirebase(User? user) {
    if (user != null) {
      return UserModel(uid: user.uid);
    } else {
      return null;
    }
  }
  Future<void> logIn(String pEmail, String pPassword) async {
    try {
      await _fireAuth.signInWithEmailAndPassword(
        email: pEmail, password: pPassword);
    } on FirebaseAuthException catch (e) {
      final ex = AuthExceptions.code(e.code);
      return Future.error('${ex.message} - ${e.code}');
    } on SocketException catch (e) {
      return Future.error('Web Socketn($e)n(${e.osError})');
    } on PlatformException catch (e) {
      return Future.error('Platformn($e)n(${e.message})');
    } catch (e) {
      return Future.error('Unexpectedn($e)n(${e.toString()})');
    }
  }

…

My question is: Do I have to check if the user is logged in on everyscreen of the app? let’s say at the top of every screen call some method and ask Provider if the user is still logged in? Any comments on this or about the code would be really appreciated.
Thanks.