Should I load all "package dependencies" in tufte-latex?

Question

In the tufte-latex sample-book.pdf:

Package Dependencies
The following is a list of packages that the Tufte-LATEX document classes rely upon. Packages marked with an asterisk are optional.
• xifthen
• ifpdf*
• ifxetex*
• hyperref
• geometry
• ragged2e
• chngpage or changepage • paralist
• textcase
• soul*
• letterspace* • setspace
• natbib and bibentry • optparams
• placeins
• mathpazo*
• helvet*
• fontenc
• beramono* • fancyhdr • xcolor
• textcomp • titlesec
• titletoc

Does this mean that I

• should load all these explicitly,
• that they are loaded automatically or
• that they can be loaded if they are really needed?

Answer 1

The packages are loaded by tufte. You don't have to do anything:

\listfiles
\documentclass{tufte-book}
\usepackage{blindtext}% only for demo here
\let\subsubsection\subsection%  dito
\begin{document}
\blinddocument
\end{document}

The filelist (can be found at the end of the logfile):

 *File List*
tufte-book.cls    2009/12/11 v3.5.0 Tufte-book class
tufte-common.def    2009/12/11 v3.5.0 Common code for the Tufte-LaTeX styles
 xkeyval.sty    2012/10/14 v2.6b package option processing (HA)
 xkeyval.tex    2012/10/14 v2.6b key=value parser (HA)
 xifthen.sty    2009/04/17 v1.3 Extended ifthen features
    etex.sty    1998/03/26 v2.0 eTeX basic definition package (PEB)
    calc.sty    2007/08/22 v4.3 Infix arithmetic (KKT,FJ)
  ifthen.sty    2001/05/26 v1.1c Standard LaTeX ifthen package (DPC)
 ifmtarg.sty    2009/09/02 v1.2a check for an empty argument
    book.cls    2007/10/19 v1.4h Standard LaTeX document class
    bk10.clo    2007/10/19 v1.4h Standard LaTeX file (size option)
   ifpdf.sty    2011/01/30 v2.3 Provides the ifpdf switch (HO)
 ifxetex.sty    2010/09/12 v0.6 Provides ifxetex conditional
titlesec.sty    2011/12/15 v2.10.0 Sectioning titles
titletoc.sty    2011/12/15 v1.6 TOC entries
hyperref.sty    2012/11/06 v6.83m Hypertext links for LaTeX
hobsub-hyperref.sty    2012/05/28 v1.13 Bundle oberdiek, subset hyperref (HO)
hobsub-generic.sty    2012/05/28 v1.13 Bundle oberdiek, subset generic (HO)
  hobsub.sty    2012/05/28 v1.13 Construct package bundles (HO)
infwarerr.sty    2010/04/08 v1.3 Providing info/warning/error messages (HO)
 ltxcmds.sty    2011/11/09 v1.22 LaTeX kernel commands for general use (HO)
ifluatex.sty    2010/03/01 v1.3 Provides the ifluatex switch (HO)
  ifvtex.sty    2010/03/01 v1.5 Detect VTeX and its facilities (HO)
 intcalc.sty    2007/09/27 v1.1 Expandable calculations with integers (HO)
[...]