Numbering of Appendices in Latex

Just fixed the appendices for my thesis so that they work properly for me.

Wanted behaviour:

• give me a separate heading 'appendices' in the toc
• after 'appendices' come the appendices with A app 1, B app2, ...
• tables, equations, figures are named correnspondingly (A.1, ... )
• avoid warnings from the hyperref package about doubly defined pages/tables/...
  

This can be achieved like this:
\appendix is the usual command to start appendices, leading to A name_of_chapter/section in the table of contents and as heading. The equations/figures/tables would though keep their numbering - with
\numberwithin{equation}{section}
\numberwithin{table}{section}
\numberwithin{figure}{section} it can be adapted to A.1 and so on.
In my case I have a big document, so I include the appendices from a separate file. Now is the time to do so
\include{appendices}
because the following commands
\appendixpage
\addappheadtotoc
exhibit unwanted behavior when invoked out of the included file. The first command adds a heading 'Appendices' before the appendices in the text and the second one adds a similar line to the table of contents (thanks to here for this tip).
An appendix is then created with the following command:
\section{Name of Appendix}
\label{sec:appendixA}

For the numbering the package amsmath has to be included, for the additional appendix commands the appendix-package is needed:
\usepackage{appendix}
\usepackage{amsmath}