Depends on your body, how old the piercing is, and what size the piercing is.
Wait at least 8 weeks before you change the jewelry.
Yes. If they are long though, you might want to shave or wax just to keep the hairs from getting caught in the piercing.
Honestly it don't matter where the belly piercing is . As long if ain't to low where it can rip out . If i. Where u I would be carefull
10hrs
you can get your naval (belly) piercing at 13-17 as long as you take an adult and the same applys with the tongue piercing but they may tell you to wait until you are 14
A navel piercing can take anywhere from six months to a year to heal completely.
2-3 months
give it about a week or so it will be okay
After 3 years chances are good it wont close, the piercing will shrink but not close completely.
a week at most
you should wait 8 weeks. at least but really its whatever the piercing place told you