If you have citrus trees on your layout of the 1910-70's era, then you'll need these smudge pots to keep your investment from freezing on cold days. Smudge pots were developed after a disastrous freeze in Southern California in January, 1913. With fuel prices and environmental concerns smudge pots fell out of favor in the 70s. Here also is a word from one of our customers: Regarding smudge pots... I was raised in northern California's San Joaquin Valley. Back in the 1940s and through the 1960s, perhaps later, smudge pots were used in almond orchards too, probably because of the early blooming season for almond trees. So one does not have to model southern California to use these details