>>Isn't that more of an issue of coding practices rather than using a variable vs defines? I can do the same thing you just said with variables.
>>
>Not exactly. If you define your constants in the include file, that's the only place where you would need to change them if used in multiple forms/programs.

If I defined a variable in my main program as a constant (MY_CONSTANT = 10) then there is only one place I need to change it too. Just not getting the real difference here that actually makes a difference in development. I always thought they were something special, but they are just variables that dont change value. If I treat them as constants, then they are constants. What am I missing?