If you find you are tossing a bunch of prey because young snakes are no longer feeding as strongly it may be a seasonal effect - most of ours (corns and kings) slow down in the fall/winter even before brumation.
While we try to keep to something of a schedule with feeding for our convenience, we do wait for some evidence that they are hungry before offering food. I expect to see them out looking for a couple days or so before feeding day or they are off the list to get anything offered that week. For those that are secretive, like the young hondurans, I want to see a couple nights in a row where there are lots of trails in their bedding before a day that they are fed. While we feed the largest prey they can readily handle, I prefer to let them get hungry between meals. If they are not out it is likely that they are coming into shed or just not in the mood to feed. Of course we check everyone daily and keep records of feeding on the tub and on a record sheet in the snake room so that if someone has an extended period where they haven't fed we are checking up on the reason.