It can be hard work persuading people of the importance of having their work checked before it goes to print, or online. It’s a popular notion that proofreading is all about spelling. Of course, spelling is very important, but so is the way in which you construct a sentence. Punctuation is absolutely key, otherwise your meaning can be lost.
Page numbers on your table of contents might not match up to chapter titles, the figures on your pie chart are in the wrong segments, footnote citations end up on the wrong page, weblinks don’t link, running heads are not in the right place, there are clumsy line, paragraph and column breaks (not to mention those pesky widows and orphans), hyphens where there should be dashes, sneaky extra word spaces, columns not aligned vertically, glitches in the leading, captions matched incorrectly to images, rogue apostrophes, poor hyphenation, inconsistent capitalisation – the list is long!
Having your work proofread always pays dividends. Mistakes give the impression of carelessness, which undermines your credibility.