This varies from perosn to person and also how long you have had the piercing. Never remove a piercing for more than a few minutes if it is less than a year and a half to two years old, simply as a precaution. If it is old enough the best way to check is to remove your piercing in the morning when you get up and periodically (every four hours) slip the jewelry back in and see if it's stiff or still loose. If it stays loose throughout the entire day add an hour or two to how long the jewelry is out. If you can go 16 or more hours without it getting stiff I would then leave it out over night (your body heals better at night when you are resting) and try to put it in first thing in the morning. If it's stiff then you know what you should not leave it out overnight, but during the day. This is the best way I can think to do this as it works VERY well for new (but old enough) piercings and stretched piercings.
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