Add Pages to Passport FAQ
If your passport does not have much validity remaining, you can either add pages or opt for an early passport renewal. If you do not have any valid visas in your passport that you need to continue to use, doing an early passport renewal may be the best option for you.
The standard additional pages service will add 24 visas pages to your passport, but if you are a very frequent traveler, you can request a large 48 page insert at no additional cost. You will just need to check the appropriate box when you fill out your application for additional pages.
You can have up to three 24-page inserts added, or two 48-page inserts.
If the State Department feels that your passport is not in good enough condition to have additional pages sewn in, they will tell you to renew the passport instead. They will not add pages if they think that the passport binding may break.