Or one of the biggest.
The occasional professional writer, be he writing commercial, technical or quality documents will easily fall into the trap of applying a style that he personally likes, for whatever reason.
The error is of no import if he is a sole trader, and of little import if he is the CEO. In any other situation, the writer's personal style will clash with someone else's personal style, and successive reviews by collaborators will see infinitives split and unsplit, and prepositions moved back and forth between the end and the middle of sentences, caesuras will oscillate between commas, semicolons en-dashes em-dashes stops and brackets, vocabulary will oscillate between the Latin and the Anglo-Saxon.
supervisor (latin) translates exactly to overseer (german), however these two fellows don't do exactly the same job...
And there, as our friend WS would say, is the rub.
The professional writer must apply a style that is perhaps derived from his personal style, but which is susceptible to justification and definition - in other words, that he can write it down.
The professional writer needs, for every product he describes, a list of names and references for parts. It is widely accepted that he (or a GD or publisher) will apply a graphic charter. It is surprising, perhaps, then, that very few companys have a Style Guide.
A Style Guide defines the company writing style, with the purpose of being clear, seeming educated and professional - for sure. But most of all, the purpose of a style guide is to be consistent. Endless reviews over a few points of style need not happen if there is a style guide that states, for example:
"When writing for a readership that is predominantly academic, or from a profession where a high level of competence in written communication is typical, the writer shall be careful to avoid constructions that cause them consternation, such as split infinitives, orphaned auxiliaries, overlong sentences, lists, and prepositions at the ends of clauses.
"Whenever the academics are only a small proportion of the readers, such percieved grammatical "errors" are no cause for concern, indeed in some cases going out of your way to avoid them will cause confusion in the majority of readers. For example, in many cases, moving a preposition away from the end of a sentence may make a sentence read unnaturally. It also usually forces the particle "which" into the sentence, which for most readers adds no meaning."
I have recently had a whole series of paragraphs to review where the prepositions were better at the ends of the sentences, because in spoken English they are almost never separated from their verb.
"This is the one into which you must put it."
Is hateful, when compared with:
"This is the one you must put it into."
I didn't intend this to become a discussion of any specific point. The point in question here is that efficiency in technical writing cannot be acheived unless the issue of style is laid utterly to rest. This can only be done through the elaboration of a style guide. There are many templates available, and the Economist Style Guide is probably the best starting point, for its simplicity and brevity.
I commonly use structures and vocabulary in professional writing that in creative writing I would never stoop to. However, in professional writing, I would never stoop to fussing over good or proper style. In professional writing meaning is everything, and style has to be basic, simple, unobtrusive and most of all, CONSISTENT.