>You talk about #DEFINE used in ordinary code ? so not about headerfiles are you

Yes, ordinary...

>IMHO you only use locals when they can change during runtime. If they don't you can:
>
>- use hardcoded values
>- use #DEFINE if this value applies to more than one instance in code, so maintainability is increased.

I'm thinking mainly of constants for things like SYS() calls. The constant is supposed to be faster, but is not available debugging, either.