One can use storebox package to save space.
For example, I will expect that this works as it is similar to the use of savebox. However, it does not. One needs to move the \storebox{\foobox}{FOO} inside the \begin{document} to use it.
\documentclass{article}
\usepackage{storebox}
\newstorebox{\foobox}
% moving this line inside begin{document} works
\storebox{\foobox}{FOO}
\begin{document}
\usestorebox{\foobox}
\end{document}
Now, consider this
\documentclass{article}
\newsavebox{\foobox}
\savebox{\foobox}{FOO}
\begin{document}
\usebox{\foobox}
\end{document}
This option with savebox works.
So, how can I make the use of \storebox before \begin{document} work as savebox?
\saveboxnor\storeboxshould be used before\begin{document}. – egreg May 25 '15 at 22:26