If you’re away for long trip, you’ll have to do a wash at some point. But if you’re gone for a week or less and don’t fancy doing a hotel-sink rinse, just pack extra delicates, especially if you have an active trip planned. After a day of kayaking/swimming/hiking/etc, the last thing you want to do postshower is put on a less-than-fresh pair.
I have my preferred travel credit card, but I always carry a spare or two because you never know when for some reason it won’t process. Or – even worse – you lose it or it’s stolen. Also, if you need to withdraw cash overseas, some ATMs can be finicky with accepting cards (I find Amex almost always works in those cases).
When travelling, it never hurts to be prepared for the worst-case scenario. A mechanical error could ground your flight for an extra night. A hurricane could see you stranded for days. And when things go sideways the last stress you need is trying to find a doctor and pharmacy. Pills don’t take up much room, so always throw in a few extra.
Every road warrior I know always packs empty Ziploc bags. It’s surprising how often they come in handy for storing snacks, encapsulating leaking bottles, storing wet bathing suits - you name it. If you want to be more green, go for a plastic-free, reusable option. An extra tote or compressible duffel bag is also good for souvenir overflow.
For those old-school photography fans who still pack a camera along with a smartphone, make you sure you toss at least one extra battery and memory card into your bag. In colder weather, a battery can die shockingly fast, and you don’t want to miss that perfect shot because you’re busy deleting pics of Aunt Pam’s 90th birthday to free up space.