Lets say, you are already loaded data from a service and after some time the data is changed in the service, the bounded model is not updated. The solution is very easy, add an Input decorator to the variable. As mentioned on the Angular site:
Declares a data-bound input property, which Angular automatically updates during change detection.
Just add '@Input()` before your property name and use it directly in the template, the model will be updated automatically on changes.
//In myservice
@Input() isVisible: boolean;
//In another component template
<div *ngIf="myservice.isVisible"></div>