Often there will be a timer (perhaps in the electric meter box or perhaps elsewhere). Ours is in the laundry.
In Canberra a booster will be needed heaps more than in Brisbane. But I once rented a place in Canberra where we didn't even realise that there was a booster for six months- until late...
We have solar hot water and it's fine. Although we do have an electric booster so I don't know how much is solar vs electric.
At the same time we got it we started doing out market Mexican food- so we were cooking a lot more and running an extra fridge and freezer- the power bills were similar...
