Chimney clearance pruning is easy to overlook nowadays because, for various reasons, chimneys are becoming obsolete. Modern homes lack them completely.
Some chimneys of older homes succumbed to earthquakes. Because of simpler and cleaner alternatives for heat, remaining chimneys and their fireplaces, as well as firewood, are almost passe.
Ironically, chimineas and fire pits have become a fad. Most modern fire pits use propane for fuel, but a few use firewood. Although such fire pits and chimineas burn less firewood than fireplaces, they are ridiculously less efficient.