Is a php interface redundant for apps build by a single developer ?
My question is : in PHP are interfaces really useful for developers that build website applications on their own ? Isn't an abstract class providing all the things an interface provides ?

If an interface is just a "contract" isn't the developer aware of the things the class should implement ? 

The only single benefit I can think of is that a class can implement multiple interfaces but again how useful is this .. when you know everything a class should implement. You just force yourself to implement those methods.

As you can figure out I'm still waiting for that A-HA moment when I really understand why an interface is useful.

**To wrap this up and put it simple : When should I use interfaces and why not use abstract classes instead ?**

Is a php interface redundant for apps build by a single developer ?
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My question is : in PHP are interfaces really useful for developers that build website applications on their own ? Isn't an abstract class providing all the things an interface provides ?

If an interface is just a "contract" isn't the developer aware of the things the class should implement ? 

The only single benefit I can think of is that a class can implement multiple interfaces but again how useful is this .. when you know everything a class should implement. You just force yourself to implement those methods.

As you can figure out I'm still waiting for that A-HA moment when I really understand why an interface is useful.

**To wrap this up and put it simple : When should I use interfaces and why not use abstract classes instead ?**
