Advantages:
It’s a reliable method of birth control.
You don’t have to think about it every day.
If you want to become pregnant there is a rapid return to fertility, with ovulation occurring during the first cycle after discontinuation.
Nobody has to know, so it’s a good method if your parents are against contraceptives (and you plan to have sex anyway).

Disadvantages:
You may forget to take it out after three weeks or forget to put in a new one.
Side effects may include headache, vaginal discharge, vaginitis and irritation.
Does not protect you against STD’s.