Genevieve, I don't think it hurts to rework treasuries. I've done that with a few of mine that have gotten really good views. (For me, anything over about 250 is really good.) I tweak the tags while I'm at it so that, hopefully, it stays relevant. If they're more than a few months' old, though, I wouldn't bother. It'll be easier and more relevant to simply do a new one.