All LLD Macros are only usable as "dynamic" macros.  It would be nice if you could add a feature to mark the used macros as static ones. E.g. "!{#TIMESTAMP}" additionally to "{#TIMESTAMP}".

Currently it's not possible to save a information of item creation permanently. If the information in LLD changes than the change is enforced in all locations where the macro was used.
I want to use the LLD macro only at item creation and ignore it's value for further LLD intervals if the item already exists. So that the Item keep the value of first discovery.
But only for specific macro. Not for all.

Usage scenario:

LLD get a list with 2 attributes {#NAME} and {#TIMESTAMP} (I know syntax changed with 4.2, but old scheme is easier ).
{#TIMESTAMP} has ever the current time in it. You want to build a trigger that checks how long the item exists. Trigger knows now() but not the creation time of the item. With a static LLD macro it would be possible to use !{#TIMESTAMP} of item creation as parameter of item key and calculate the age of the item (via calculated item, external check or what ever).

That could also be useful for many other things that are discoverable.