psutils may not only save paper, they are also a great tool to produce a convenient page design. Imagine a nice bounded manual in A5 format, against a losely hefted block of A4 sheets.
Depending on wordlength and paragraphlength a multi-column layout sometimes saves paper space (though the likelihood for a word to be broken increases, on the other hand the space used by incomplete lines at the end of paragraphs decreases). This doesn't save very much paper, but may fit 2.1 pages in 2.0, therefore with the use of
psnup it may fit on one page. Also multicolumn layout is better readable.
Thanks to Ralf Muschall for his suggestions.