None of my pet dragons or skinks have ever shown any inclination to down to brumate , I've got eastern bluetongue skinks and central bearded dragons and have also had eastern water skinks.
I live in the natural range of the two species of skink and the have these in my garden/yards and under my house and in my shed. I'm also in the natural range of eastern bearded dragons and eastern water dragons and see these in my yard occasionally too.
The resident wild skinks disappear from about late Apr / early May and don't start showing up again til about late july or August and the first new babies appear in early Sept. Only the babies and juveniles are seen over winter (if there are a few warm days)
I'm told by the local kids the water dragons are often seen along the local creek and in the local remnants of natural bush year round.
I expected my skinks and dragons to brumate too, but it's never happened, everyone stays awake and is out basking every day and keen for their food and floor fun time over winter. Only difference I've seen is they like longer sleepins and go to bed a bit earlier.
My situation :
>>climate controlled home , aircon running 24/7 to hold 23oC overnight and 25-26oC during the days in winter, rarely colder than 23oC inside my house.
>>Lizards vivs and rearing vivs are in the family area and in the warmest area of the house (in winter)
>>I run my lights same photoperiod year round ( on 6am , off 10pm ).
>>I don't adjust temps or photoperiod over winter (if any of my pets was showing it wanted to brumate and it was over 12 months old (all are now) I would accommodate it but I don't see the point.
In the wild brumation is a survival strategy and a response to the dry season (winter) and a big reduction in the amount of food for their prey insects and smaller prey reptiles and animals and the lack of green leafy herbs , edible flowers, and fruits , these tend to die off due to lack of rain, than a response to temperatures .
Brumation for a captive / pet reptile is unnecessary as food is available year round. It may be beneficial for captive breeding pairs to induce brumation in them and I understand many/most breeders do this so their get larger clutches and better fertility.