Birth control pills can be started at different times depending on the individual and the type of pill being used. Here are a few common options:

1. On the first day of your menstrual cycle: This is the most common time to start taking birth control pills. If you start the pill on the first day of your period, you'll be protected against pregnancy right away.

2. Within the first 5 days of your menstrual cycle: If you start the pill within the first 5 days of your period, you'll be protected against pregnancy right away.

3. Within the first 5 days after giving birth: If you have given birth and are not breastfeeding, you can start taking birth control pills within the first 5 days after giving birth.

4. Within the first week after having an abortion: If you have had an abortion and want to start taking birth control pills, you can start taking them within the first week after the procedure.

5. The quick start method involves starting the pill on any day you choose, even if you're not on your period. You'll need to use a barrier method, such as a condom, for the first 7 days of pill use to ensure protection against pregnancy. After 7 days of taking the pill, you will be protected against pregnancy.