Noodles enjoys leaving me one GIANT surprise every two to two and a half months. Every snake is different though... Some poo 2-3 days after every feeding, some once every two weeks, once a month, etc... I feed her on a 5-7 day schedule regardless. She pees and passes urates normally in this time, but saves up her poop for a while.
Both of mine give me a surprise once about every month-month and a half. They pass urine much more regularly, and usually shed a couple weeks after their bowel movement.