Re-insert equation by label

I read over the response given here: Is it possible to re-insert a LaTeX equation by label? which says such a thing is possible only with a macro. I would like to do this.

I have a bajillion equations, some labelled and some not. Of those that are labelled, some I would like to display again, say, at the end of the document as a quick summary. Wome equations I want to show twice at different places identically.

The problem is I can't decide on notation and I keep changing small things and it is a bit of a pain to remember which equations I want to display again and if I've updated them or not.

Would there be a obvious/better way to do this?

I have to admit I haven't ever bothered with macros for latex before today so apologies if the following is horrible, but, (to the best of my understanding) is that it would be something like

\newcommand{\acommand}[2]{%
#1
\expandafter\newcommand\csname #2\endcsname{#1}%
}

\acommand{someequation}{equationassociated} \\
\equationassociated


So then \acommand{someequation}{labelassociated} will display someequation and define the macro \labelassociated.

But then, what if I want to display someequation along with the label entered as the second argument?

-
Could you please provide a minimal working example (MWE) that shows your use case? –  Werner Dec 31 '12 at 8:23
Yes, what if? What is the question here? If you create a macro, e.g. \newcommand*{\reuseeq}[1]{\csname #1\endcsname}, and use it with the associated labe, e.g. \reuseeq{labelassociated} you’d get someequation again. Related: How do I show the equation formula again instead of its number of ref? –  Qrrbrbirlbel Dec 31 '12 at 8:32

For a lot of equations, specially if they must be reused, for me the best approach are external files, each with one raw equation and include in the master simply with \input{path\filename} or a macro that do this plus surround it with the desired environment, add appropriate labels based in the filename and/or path, etc.