Should the prefix "re" be added to a word with or without a hyphen?

Solution 1:

It depends on how recent the words are. If you are concerned that your meaning will be unclear, by all means use the hyphen. Words like reentry and reelect have been in usage for a long time and pretty much no one has a problem with them. Reexcite has not, so you would do better to stick with re-excites. If you want to edit something again, you are probably better off to re-edit it if you are worried that reedit will cause the reader to stumble.

Where the prefix is not followed by a vowel, however, you are not honor-bound to add the hyphen. If you want to repolarize something, go right ahead. According to Etymonline, the word repurpose is less than 30 years old, having dropped its hyphen somewhere in the early 1980s. So if you are the first to repolarize something, you are not likely to be the last, and you will probably start a trend. In any case, your meaning will be clear.

Solution 2:

The only thing to add to Robusto's answer is that sometimes there's no choice but to keep the hyphen, to prevent confusion. For example, recover ("get something back") vs. re-cover ("cover again").

Solution 3:

There are two tests for deciding:

First, which way do most of your colleagues do it, reparameterized or re-parameterized?

Generally, it's standard operating procedure (SOP) to imitate your peers and colleagues because that's what they expect to see.

Second, will the version without the hyphen cause confusion or force the reader to waste time by having to look at the word a second time?

If the outcome of the second test is Yes, then use the hyphen.

There may be a third test. British English writers generally use hyphens more often than American English writers. If you're writing for a European journal or an audience of British English speakers, it might be better to use the hyphen. If the audience is primarily American, it might be better to omit the hyphen.

I don't think there should be any confusion without the hyphen, but that's just a personal opinion. Ask a couple of colleagues how they would write it.