\medskip after every paragraph

Question

After every paragraph I write, I use \medskip all the time e.g.

\begin{document}

test test test

\medskip

test test test

\end{document}

Is there a way to automate this so I don't need to type in \medskip all the time?

Also, out of interest, medskip is defined as 6pt plus 2pt minus 2pt for book and article classes. But why not simply 6pt?

Answer 1

The space between paragraphs is controlled by \parskip, you can set that length to \medskipamount (the length of \medskip).

You may or may not want to additionally set \parindent to zero.

It is slightly more comfortable to let the package parskip do that for you. (It also patches a few commands to avoid additional excessive space, so it is usually preferred over simply changing \parskip for the whole document.) The code below assumes parskip v2 (2018-08-24) or above.

\documentclass{article}

\usepackage[skip=\medskipamount]{parskip}
\usepackage{lipsum}

\begin{document}
\lipsum[1-4]
\end{document}

Some document classes may offer additional interfaces to change \parskip and friends that should be preferred over just setting \parskip directly. With KOMA-Script classes you would either be using the parskip option or \setparsizes{<indent>}{<skip>}{<last line end-space>}.

\documentclass{scrartcl}

\setparsizes{0pt}{\medskipamount}{0pt plus 1fil}

\usepackage{lipsum}

\begin{document}
\lipsum[1-4]
\end{document}

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The plus and minus bit are not literally 6+2-2=6, they allow for stretchable space (can stretch by 2pt) and shrinkable space (can shrink by 2pt), so that you get 6pt that may stretch or shrink a bit.