I suggest it, I have to leave it in for at least 2 of mine because they are so paranoid. I currently only have one that won't take any f/t prey I've offered, overnight or not. That still leaves 8 success stories a majority of the time lol. Of course those stats shouldn't include my normal male who's a garbage disposal...or my boa who eats anything that dangles in his tubBut my other 2 that require it, it's usually a good 70-80% chance they eat it overnight when no ones looking...