A layover at JFK.

Yes, if you're arriving from another country. Every international arrival at JFK clears passport control and customs, collects and rechecks checked bags, and goes back through TSA security before a connecting flight, even a domestic one. The exception is a flight that was precleared before departure, such as from Canada, Ireland or Abu Dhabi. Domestic-to-domestic connections stay airside.

LYVR shows live security wait times for each checkpoint, grouped by terminal, refreshed every couple of minutes.

LYVR shows the average customs wait for the current hour over the latest week, for US citizens and visitors, from US Customs and Border Protection's own data.

LYVR lists 22 lounges at JFK, 9 of them on Priority Pass. Which ones you can get into depends on your ticket, airline status, credit card or a lounge membership. Each lounge on this page lists what gets you in, and LYVR checks it against your own profile.

Capital One Venture X: Capital One Lounge; Capital One Venture X Business: Capital One Lounge; Amex Platinum Card: The Centurion Lounge; Amex Business Platinum Card: The Centurion Lounge; Amex Centurion Card: The Centurion Lounge; Amex Delta SkyMiles Reserve: The Centurion Lounge; Chase Sapphire Reserve: Chase Sapphire Lounge by The Club with Etihad Airways; Chase Sapphire Reserve for Business: Chase Sapphire Lounge by The Club with Etihad Airways; Chase J.P. Morgan Reserve: Chase Sapphire Lounge by The Club with Etihad Airways; Chase Ritz-Carlton Card: Chase Sapphire Lounge by The Club with Etihad Airways. Card benefits change, so check your card's terms before you go.

Yes, at 12 lounges: Air France Lounge (Air France Gold and up, SkyTeam Elite Plus); Korean Air Lounge (Korean Air Morning Calm Select and up, SkyTeam Elite Plus); Lufthansa Business Lounge (Lufthansa Frequent Traveller and up, Star Alliance Gold); Turkish Airlines Lounge (Turkish Airlines Elite and up, Star Alliance Gold); Air India Lounge (Air India Gold and up, Star Alliance Gold); Delta Sky Club (SkyTeam Elite Plus). Status entry needs a same-day departing flight on that airline or its alliance, and some tiers only count on international flights.

It depends on your terminals, whether you re-clear security or customs, and how far the gates are apart. LYVR adds up deplaning, every walk on the indoor map, any checkpoints your connection passes and the boarding door time, then shows exactly how much time you have to spare.

For a domestic connection on one ticket, usually yes, even with a terminal change: the longest move between terminals at JFK is about 22 minutes. Arriving at JFK from another country, no: you clear passport control and customs, collect and recheck checked bags and go back through TSA security, so plan on 2.5 to 3 hours, unless your flight was precleared before departure. If a delay makes you miss a connection on one ticket, the airline rebooks you. LYVR works out your exact time to spare for your own two gates.

With an hour or two, eat near your gate and walk the terminal. With more, JFK's 22 lounges (9 on Priority Pass) have quiet seats, food and often showers, and there are gaming lounges, sleep pods, sleep suites and spas you can use with Priority Pass. LYVR's Explore tab lists every restaurant, bar and shop near your gate with the walk time, so you only see what fits in your layover.

Yes, if you have time. Arriving from abroad, you've already cleared US immigration and customs at JFK, so leaving only adds the trip into New York and back and TSA security on the return. As a rule of thumb, it's worth it with about 4 hours on a domestic layover and 6 on an international one. LYVR checks the ride each way and how much time you'd really have in New York.