How does the concept of 'electron shells' or 'energy levels' further refine our understanding of electron 'orbiting'?

Electron shells or energy levels suggest that electrons don't orbit randomly, but occupy specific regions at discrete energy states around the nucleus. This explains the quantized nature of electron energies and how they absorb and emit light.
The Bohr model and later quantum mechanical models introduced the idea that electrons exist in specific energy levels or shells. This isn't a simple planetary orbit but a probabilistic distribution of electrons within these defined energy regions, explaining atomic stability and spectral lines.