Mother would put them on, bring them to a boil, simmer for about an hour, at which time she would add bacon drippings, sugar, and salt. If she had left over ham, she would put the trimmings in at the beginning of cooking. After seasoning the beans, they simmered for at least 30 to 45 minutes. I cooked my that way too, until I found out all that fat was lodging in my arteries.