Weigh your bags (or pay the price).
This is one of those things that separates the travel pros from the travel schmoes.
A travel pro knows what luggage is allowed to weigh before the airline makes you pay for half a tank of jet fuel for daring to bring too many sweaters aboard. A travel schmo gets mad at the person behind the counter for delivering this news.
A travel pro weighs their bags before they head out the door. A travel schmo crosses their fingers nervously while dumping their stuff on that big scale at the airport.
You get the idea—no wait one more: A travel pro can manage to sit on an airplane for a few hours while wearing actual pants. A travel schmo for some reason devolves into a toddler wearing pajamas and cuddling a blanket anytime they need to hop more than one time zone.
Sorry, that last one is not strictly relevant.
Well we can’t talk anybody out of wearing their SpongeBob footie PJs to LAX, but we can hook you up with a pair of very elegant and super useful luggage scales for twelve bucks.
Keep one at home and keep one in your bag. (Travel pros know that weight limits apply to the return trip, too, and buy their souvenirs accordingly…)