You don't mention what kind of thesis you have, pictures and so on, so I'm just going to go with what I got. I'd put the two parts in environments and \excludecomment them using the comment package.

\documentclass{article}
\newenvironment{partone}{}{}
\newenvironment{parttwo}{}{}
\usepackage{comment}
%\excludecomment{partone}
\excludecomment{parttwo}
\usepackage{filecontents}
\begin{filecontents*}{mychapter.tex}
\begin{partone}
Part one of your thesis
\end{partone}
\begin{parttwo}
Part two
\end{parttwo}
\end{filecontents*}
\begin{document}
Tableofcontents
\input mychapter.tex
Chapter 2,3,4,5
\end{document}
For completeness, I will also include something to externalize images (as mentioned in comments to the question). The image below doesn't mean anything. I just wanted to use something with at least some compilation time. You will need to run pdflatex (or whatever engine you require for your thesis) with the shell escape option to make use of this method.
\documentclass{article}
\usepackage{tikz}
\usepackage{tikz-3dplot}
\usetikzlibrary{external}
\tikzexternalize
\begin{document}
\tdplotsetmaincoords{65}{155}
\begin{tikzpicture}
[scale=5,
tdplot_main_coords,
axis/.style={->,black,very thin},
vector/.style={-stealth,black,thick },
curve/.style={black,thin}]
\coordinate (O) at (0,0,0);
\draw[axis] (0,0,0) -- (1.2,0,0) node[anchor=north east]{$x$};
\draw[axis] (0,0,0) -- (0,1.2,0) node[anchor=north west]{$y$};
\draw[axis] (0,0,0) -- (0,0,1.2) node[anchor=south]{$z$};
\draw[axis,dashed] (0,0,0) -- (-1.2,0,0) node[anchor=south west]{};
\draw[axis,dashed] (0,0,0) -- (0,-1.2,0) node[anchor=south east]{};
\tdplotsinandcos{\sintheta}{\costheta}{45}
\draw[vector,green!80!black] (0,0,0) -- (.62*\costheta,.62*\sintheta,0) node[above=.27in,right=.03in] {\Large $\rho$};
\tdplotsetthetaplanecoords{0}
\tdplotdrawarc[curve,tdplot_rotated_coords,thick,magenta!80,<-]{(O)}{1}{0}{90}{}{}
\node[magenta!80] at (.8,0,.8) {\Large$\phi$};
\foreach \angle in {0,30,...,180}
{
\tdplotsinandcos{\sintheta}{\costheta}{\angle}%
\coordinate (P) at (0,0,.62*\sintheta);
\tdplotdrawarc[curve,very thin]{(P)}{.62*\costheta}{0}{180}{}{}
}
\tdplotsinandcos{\sintheta}{\costheta}{180}
\tdplotdrawarc[curve,thick,cyan!80,->]{(P)}{.8*\costheta}{-90}{260}{}{}
\node[cyan!80] at (.7,.7,0) {\Large$\theta$};
\foreach \angle in {0,30,...,360}
{
\tdplotsetthetaplanecoords{\angle}
\tdplotdrawarc[curve,tdplot_rotated_coords,very thin]{(O)}{.62}{0}{90}{}{}
}
\end{tikzpicture}
\end{document}
TiKZfigures which are everytime compiled, tryexternaltikzlibrary to just compile them when needed. Another solution could be to usestandalone. – Ignasi Apr 17 '15 at 11:05chapter4.texwhich contains\chapter{Name of chapter} \input{chapter4part1} \input{chapter4part2}and comment or no one of these\inputaccording what you want to see. – Ignasi Apr 28 '15 at 10:13