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After a comment of @DavidCarlisle in a question about vspace usage I tried to find out if, when and why a vspace command should be avoided to added as a last command of a paragraph in order to add or to remove space between paragraphs, like:

This is the text of a paragraph here.vspace1cm

This is the text of the next paragraph.

@DavidCarlisle answered in a comment of mine that:

"the blank line should be before the vspace. Using vspace in horizontal
mode is well defined but weird, you almost always want to avoid that."

So, the proposed "correction" (as far as I can understand) is:

This is the text of a paragraph here.

vspace1cmThis is the text of the next paragraph.

But I tried many examples and didn't found one that would give an unexpected output (in order of vertical spacing, but general too). Also, in my first LaTeX steps I was using this style:

This is the text of a paragraph here.

vspace1cm

This is the text of the next paragraph.

that now seems awful to me but could be consider as better LaTeX coding from my first example (the style that I am currently using).

So, my question is:

**

1. 
   Should I avoid the coding style of the first example for some reason?


2. Is there any example that my style will fail in the expected spacing? (or this is just about code style)

MWE:

documentclassarticle
usepackageparskip
usepackagetikz
usetikzlibrarycalc
usetikzlibrarypositioning
setlengthparskip1cm plus 0cm minus 0cm
setlengthparindent0pt

newcommandexpectedVSkip[2][2.2cm]begintikzpicture[overlay,remember picture,baseline=0pt]node[use as bounding box,inner sep=0,outer sep=0] at (0,0) (A)vphantomtextttp;draw[->,blue] (A.south)--node[midway,right]$#2$($(A.south)+(0,-#2)$);draw[->,thin,blue] ($(A.south)+(-#1,0)$)--($(A.south)+(0,0)$);draw[->,thin,blue] ($(A.south)+(-#1,-#2)$)--($(A.south)+(0,-#2)$);endtikzpicture

begindocument

This is the first paragraph that will have a space of the verb|parskip|$=1;cm$ length from the following command since no verb|vspace|expectedVSkip1cm command is added here.

This is the second paragraph that will have a space of $0.5;cm$ from the folowing paragraph since a verb|vspace-0.5cm|expectedVSkip0.5cm command is added just in its end.vspace-0.5cm

Thisvspace2cm is the third paragraph with a verb|vspace2cm|expectedVSkip2cm command before the end of its first line. The paragpaph have enough text following, in order to let us discover if the verb|vspace| will act from the point of the first linebreak or from the end of this paragraph (Since the command is placed in its first line, the command is supposed to act just at the place that LaTeX will deside to break the line and the paragraph will be an ugly broken paragraph with a strange added vertical space of exactly $2;cm$). After this paragraph the following paragraph will be in distance of 2cm since an additional (just one) $cm$ have been added through a verb|vspace1cm|expectedVSkip2cm to the verb|parskip|.vspace1cm

This is just the fourth paragraph.


enddocument

and output of MWE:

PS: I will not tag the question with tikz tag, because I just used that to demonstrate the distances and to make them visible, feel free to use the command even if you have no idea about tikz, or to just ignore it and show the possible "failing" example of my style with another way or with just clear difference in the expected vertical space (or whatever).