Sometimes instead of coming up with new ideas for scenes in movies, it's just easier to copy your own work. Check out this video that shows how Disney recycled and re-used and repurposed scenes from its movies. Sleeping Beauty is Beauty in the Beast, Robin Hood was used in Snow White and so on.
Hand-drawing animation is a tough gig! Movie Munchies writes:
Disney animators frequently used to recycle footage from older animated films. They would draw over existing animation cells to make new scenes with characters with similar designs, characteristics, and movements.