ATM card and use it at the airport if you plan to take a taxi. They don't take credit cards!

By the way, if you are flying anywhere in India, bring along your printed itinery. You can't enter the terminal with out it. Electronic boarding pass? Not adequate!

If you want / use them ----washcloths.

Keys? Never carry them. We have garage door openers, and leave the inside door open. We have a security system. There is a key hidden outside that certain people are aware of should there be power outage upon our return.

My must list is: smartphone which has about everything I need on it, charger, highlighter for paper maps/brochures to mark where your hotel/destination is. So easy, so tiny, so annoying to some Fodorites as I won something for this being chosen by editors! Obviously, credit card, some local currency, passport, medications, glasses, etc. Do people really forget these items?

>>Keys? Never carry them. We have garage door openers,<<

Me neither -- but then not everyone has a garage let alone an automatic opener. But I never ever carry my house keys on a trip.

I never take local currency (unless I happen to have some left over from an earlier trip). I wait until I'm there and use an ATM.

Hi Jose,of course there are many things must-have on your trip,but I think a powerful travel jacket which know you best will make your traveling more easy and comfortable!

Well if I didn't carry my apartment keys, I wouldn't be able to get into my home upon return.

Necessary beyond common sense.., duct Tape, Repairs anything, NO JET LAG herbals pills, wash cloths as most European hotels don't use them, something to hang your washed laundry, alarm clock

Must haves are different for everyone.
I must have a pillow that I know I can sleep on. I have found a very small but amazingly comfortable one from sea and summit.
On our upcoming Italy trip several places have a charge for towels. If I have room I will bring my microfiber towel: folds up tiny, very light, dries fabulously.

A friend used to always say
Tickets
Passport
Money (credit, debit & cash).

I would add
Toothbrush/toothpaste/deodorant. More people need to travel with the latter.
One or two changes of clothing and underwear.
Umbrella or rain poncho.
Medications as needed.
Sunscreen and insect repellent as needed.
Tablet or iPod & charger. (Used as a clock, alarm, e-reader, internet device, Dropbox electronic copies of itinerary, confirmations, etc. If I bring the one with the mini-SD slot I can store music and photos. I don't own or carry a smartphone.
Burner phone for driving vacations.
For some trips, a proper camera with charger and extra SD card and binoculars.
Extra glasses/sunglasses.
Paper copy of boarding pass, summary itinerary with confirmation numbers.
I agree re the duct tape..I never bring enough!
I actually also bring a paper check although I don't think I've ever used it.

No need to bring keys. I have a good hiding place. If I brought them I would most likely lose them, anyways.

Exchanging currency if necessary. I found out that some places simply refuse to accept anything other than their national currency. And looking for exchange points with acceptable rate is not fun.

"I found out that some places simply refuse to accept anything other than their national currency"

No kidding. And you found that surprising???? Do restaurants in your neighborhood take foreign currency?

You do not need an exchange bureau, you need an ATM card from a bank with low/no fees.

Refusing to accept anything other than there national currency! Some countries are SO unreasonable.

My new best friend of the last three years or so has been my Buff. Hat, face mask, head band and much more. A short video:

http://www.buffwear.co.uk/ways-to-wear