The truth is that "brumation is only one of many cues that wild snakes use. Light cycle, temps, precipitation, and prey abundance all probably play a roll in nature. While not necessarily a requirement for "southern" snakes, what it provides is a timeline that has proven predictable and repeatable. It is the one cue that fits neatly into our box. If you housed them year round breeding may occur w/o any cycling. But when to put them together? When to add the nest box? I suppose you could buy an ultrasound machine and look for follicular development. Or simply follow the formula that works.