How long after getting a cartilage piercing should it be all right to sleep with the earring out?

If you plan to wear it during the day, but just take it out at night you can start as early as when you take it out for the first time, after the initial 6 week-2 month period.

correction 6 weeks is when you can change them and you can only take thaem out to change them in till a year.