There are a lot of words that are known to only specialists and can make non-specialists feel like outsiders. The Plain English Campaign in the UK and its sister organisations in other countries tries to confront the problem of specialist and convoluted language in government literature especially.
But, in technical writing, there are words that we must consider are common everyday words to our audience that are not common words in everyday speech/literature. And this means we always need to be vigilant about the rules that we adapt to language use and its simplification.
For example, if you are writing some software documentation, should you spell out RAM? Do you need to? I don’t think so. But, if you were writing for an audience of librarians and you could not judge their level of computing knowledge, then maybe spelling out RAM would help them understand the concept.
The language is full of words, acronyms, and abbreviations that we don’t fully understand, but we still use them because we know we will be understood. For example, not many people nowadays know what ZIP – as in ZIP code – stands for. The answer: Zone Improvement Plan. Knowing this doesn’t help us enter our ZIP code though, does it?
So, instead of maybe adapting a rule in your style guide that states that all acronyms and abbreviations must be spelt out on first use, it could be better to state that it is worth considering if an abbreviation or acronym needs spelt out with reference to the target audience. And the same goes for specialist language – always refer back to the target audience instead of following a generic rule blindly.