My snakes have always eaten F/T and they have inexplicably left the food on the bottom of the cage a few times. They don't do it often anymore, but when they were younger, they did it every once in a while. Like another user mentioned, a couple of times they have had trouble finding the head and have given up trying to eat their food by the time I check up on them. If you want to switch to F/T, I would keep trying. I think it's worth it - it's much less trouble to keep a freezer full of frozen rats than to continually buy live ones. Of course, many people are okay with purchasing live rats on a regular basis. It depends on if you think it's worth it. But I wouldn't worry too much about the snake missing a single meal. Well-fed snakes can usually miss quite a few meals and be totally fine.