Simplicity does not in and of itself mean that you shouldn't use interfaces.

One reason to use interfaces is as you noted before to enforce contracts among classes. So that if they implement a certain behavior it will be done thru consistent method calls among all those classes.

When you notice that a substantial number of your classes, even thou they might be totally unrelated, implement a similar feature, then an interface might be called for. So you, or anyone looking at your system, can be rest assured that the feature is called in a similar fashion in any new class that might get added.

>>>>>I think the tread you were looking for is this one: Thread #1278205. Now, I am out of this thread <g>
>>>>
>>>>BTW, thanks for the link!
>>>
>>>That Thread got side-tracked a bit with the talk about "simulating mulitple inheritance", but there was still a lot of useful opinions.
>>>
>>>And the example that Bruce gave in *this* thread of how he's using Interfaces is an excellent example.
>>>
>>>If you're still having a hard time getting your head around it, ask a few more questions. We'll get you straightened out! <g>
>>>
>>>~~Bonnie
>>
>>Bonnie,
>>I think the problem I am having is that I only design simple classes and I don't need the advance functionality that you guys seem to be doing. So I assume I shouldn't use an interface for every class?
>>
>>Thanks,
>>Mike