If you are on a "self-transfer" or separate tickets where you must collect and recheck your bag, you should allow a minimum of 3 to 4 hours for a domestic layover and 4 to 6 hours for an international one in 2026. This process is time-consuming because you must deplane, wait for your luggage at the carousel, clear customs (if international), transit to the new terminal, and then stand in the check-in line for your next airline before their bag-drop cutoff (usually 60 minutes before departure). Many 2026 travelers underestimate the time it takes for bags to be delivered to the belt, which can take 30–45 minutes at busy hubs like JFK or Heathrow. A "pro-tip" for 2026 is to check if your airlines have an "interline agreement"; if they do, even on separate bookings, some agents may be able to "tag the bag through" to your final destination at the initial check-in, saving you the hassle of the "recheck" entirely. If not, always assume the worst-case scenario for security lines and baggage delays when booking your connection.