Should I use 10 cent words or $2 words?

Solution 1:

It depends on your motives. Are you trying to impress or are you trying to communicate?

As phenry noted, people who use the $2 words are trying to impress, usually both themselves and someone else. Sometimes playing politics is necessary if you want to advance. Many are not even aware that they are not communicating. They try so hard to be impressive that they fail to be useful. Unfortunately, if the rest of the people around them are the same, only those who impress will advance.

If you want to communicate, write as simply as possible, but no simpler. Know your audience, and write to them.

Solution 2:

In my world, I have no concept of words having value or beneficial qualities accorded to their length. What matters is using the best word in a given context.

As you note in your question above, register is paramount to word selection. It is up to the language user to develop a sense of what is correct and "normal" in any given situation.

Indeed, hewing to a preference for short, simple words is to render a judgement that all of one's readers are dull, uneducated plebeians - unwashed hoi polloi - who must be addressed perforce as children, with grammar-school vocabulary.

On the contrary, as William Buckley observes in his Lexicon, the taxonomy of English allows the gifted writer to amaze and delight his or her readers with occasional surprises, glimpses of the unusual, and suggestions for vocabulary improvement.

Also, different words mean different things. It is more often than not the case that a short word press-ganged into a longer one's service may miss the mark by a nuanced degree. For example:

The curator enjoined me to follow him.

Here, you cannot replace the boldface word with "asked" and preserve the meaning of the original in its entirety. Simply say what you mean and use the most precise language available to you in keeping with the appropriate register expected by your readers.

Solution 3:

• Rule 1: Don't use a $2 word where a 10 cent word will do.
• Rule 2: Don't use a 10 cent word where a 10 cent word won't do.

In other words, don't use long or obscure words purely for the sake of it - but don't hesitate to use them where they convey a particular meaning or nuance better than the alternatives.

Context is also important: in a novel (or other creative/descriptive writing) it is often more appropriate to use more varied, colourful language than in, for example, a set of instructions (where simplicity and clarity are paramount).