A lot of my customers want a shorter necklace so it sits just above the neckline of their shirt. I do 16 in, 17 in ( I know it's not a standard length but people like it) and 18 in. I've made a few 20, but nothing longer yet as they don't want to pay the price.
I tend to make my bracelets at around 7 inches long, give or take, and offer to resize if necessary. So far it's been the perfect size. However, that 7 inches is depending on the size of beads. Larger beads tend to require more length to fit even a 7 inch wrist.
I make both short and long earrings, since my customer base ranges from young to old, and every age in between. I'd like to get into hoops, but haven't yet--though I know they are popular.
Alice