My backgrounds are 3D sets, so yes, I recycle to that degree. However, one of my main character's things is teleport, so I will often do the same panel twice, the first one showing him in one position, then the next panel is the same shot showing his outline in the same position, but him in his new position. I don't have many more of those in the comic, since the reader now knows what's going on, so the rest of the script just shows a single panel with an outline and him in his new position. It was a matter of training the reader.
Also, on those, I wound up inking and colouring the panels separately, so there is always a different between them.
Eagle
(But I notice the pros do it all the time)