I do agree with Aaron’s thoughts on “It all depends on the amount of changes required”.
Still. I would use a slightly different work-flow. Meaning:
- Keep my original child theme (old-child) intact.
- Create a new folder and copy the whole old-child content in it making an exact replica. Do NOT refresh your themes screen just yet (thinking: Let me see what happened) or you may be faced with the issue: “I did this and noticed it ended up being the active theme, which I thought was strange. “.
- Turn this to a new child (new-child) theme by altering the headers in the style.css file accordingly (just a couple of lines anyway “Theme Name”, “Version”). Now it is safe to refresh and take a look to your brand new Child Theme.
- Play around to your hearts desire. 🙂
This way you get both worlds: You get to have a brand new child theme and get to keep all the useful modifications you have already so hard worked for. And the best deal? You can try it out without loosing a single visitor when combined with a plugin like Theme Test Drive or even try them out from your Appearance->Themes screen.
You can even have 2 or 3 or 5 child themes with minor modifications.
Hope that helps, marikamitsos