Avoid Repeating Yourself with \input{}

1. \input{file.tex}
   
2. Absolute Paths:
   \input{/usr/local/Curves/Curvature.tex}
   
3. Relative Paths:
   \input{Trochoids/Curvature.tex}
   
4. Avoid \include{}:
   \include{Trochoids/Curvature.tex}
   Or:
   \input{Trochoids/Curvature.tex}
\newpage
   
5. \input{} in Preamble: Yes! \documentclass{book}
\input{../Common.tex}
\input{../TikZ.tex}
\input{../TikZ.Styles.tex}
\input{../Book.tex}
\input{../MyCommands.tex}
%...
\begin{document}
   %...
\end{document}