I am far from an expert as well, I have only about a half year with my girl right now.

I give my girl two hide boxes. She uses both of them, though the warm side certainly gets used more than the cool side. She definitely doesn't use them all the time, but does like to make use of them after eating and during the daytime more than any other time. At the very least they are extra perches, and the warm box does give her some extra choices for thermoregulation (as it does provide a slight increase in temperature inside)