Have a U.S. passport expiring in 2016 or 2017? The State Department advises you start the renewal process ASAP to avoid backlogs in processing times. 2016-2017 marks the 10-year anniversary of WHTI, the Western Hemisphere Travel Initiative, which among other things required (for the first time) that U.S. citizens present a U.S. passport when departing or entering the U.S. for air travel within the Western Hemisphere. It also imposed restrictions on the acceptable documents for presentation at U.S. land and sea borders. WHTI resulted in a mad rush of U.S. passport applications, and, because U.S. passports are valid for 10 years, the Department of State now foresees a surge in upcoming renewals.
Depending on your circumstances, U.S. passports may be renewed by mail, in person, and from abroad. The Department of State offers a user-friendly website to assist in the process: https://travel.state.gov/content/travel/en/passports/have-passport/renew.html.
The New York Times offers a great report on the matter here: https://www.nytimes.com/2016/01/31/travel/passport-renewal.html?smid=fb-share&_r=0