Well, it's a matter of priority, eh? Certainly there are times you'd want the money for other purposes, especially when the going rate is high. It's still worthy getting. I don't think I've ever single-boxed WoW, so I've never considered it necessary, but at times, it's useful, and it doesn't hurt. Typically, I keep first aid up to the tier of cloth lower than the one I'm currently starting to get, and then at the end, when I'm not doing anything else, I max it out. At the very least, it gives you something to do when your other characters are grinding professions at the forge.