Java Instance Variables vs Local Variables

Question

I\'m in my first programming class in high school. We\'re doing our end of the first semester project. This project only involves one class, but many methods. My question is

Answer 1

The easy way: if the variable must be shared by more than one method, use instance variable, otherwise use local variable.

However, the good practice is to use as more local variables as possible. Why? For your simple project with only one class, there is no difference. For a project that includes a lot of classes, there is big difference. The instance variable indicates the state of your class. The more instance variables in your class, the more states this class can have and then, the more complex this class is, the hard the class is maintained or the more error prone your project might be. So the good practice is to use as more local variable as possible to keep the state of the class as simple as possible.