I have never refrozen, but I do leave them to thaw from hours to overnight. I understand why people do, whether not wanting to waste or cost. I figure it was supposed to be used anyway. I’m more likely to give uneaten to one of my more better eaters, then add a couple days till next feeding. As far as lasting in the freezer, I try not to keep them in there more then 8 to 9 months. But if packaged properly I’m pretty sure they can make a year no problem.