If you would use static methods and fields only, you would end up programming procedural like you would do with C or Pascal, loosing all the benefits of oop..so static method is used only when required and instance method is used elsewhere to get the benefit of oop.

But, I would want one more thing to be added to it:
Static methods can’t be overridden, which implies they are final methods. Rather, the concept of overridden itself should never arise because static methods are part of a class and not of an object.

But, because of the notation we abuse by writing obj.staticMethod(), people generally get confused.

Thanks,