I'm an engineer, therefore my knowledge of graphic design are very, very, very poor... so please bear with me.
I want to know how much space I should leave between two paragraphs for my thesis. I've heard from some friends of mine (who are designers) that you shouldn't if you are using indentation (that seems to be length=1em, according to Tschichold's Rules).
However, is it recommendable to use both indentation and paragraph space? (we call it
\parskip in LaTeX). If not, which one should have preference? What should be the length?