I often hesitate to create new tags, as I'm afraid that the tag will only be used in that one question. On the other hand, it is hard to tag some questions with the existing tags.
Is it correct to be cautious when creating new tags, or should I feel free to create one whenever it makes sense?
And if I do create a new tag, does it make sense to search for that keyword and tag old questions with it if it makes sense? Here I'm worried that this will be quite a lot of minor edits, which may spam the front page.
The question that brought this up for me was this one, which was tagged with
plugins, which didn't make sense to me. I think fitting tags might be
image, both of which seem to be appropriate tags for a lot of questions (I was a little surprised to see that neither exists yet, so maybe they are not appropriate tags?).