The more you know, the less you carry.
What To Pack
This Web site features an extensively annotated copy of the packing list that I use, refined over many years (and many miles) of travel, both business and pleasure; it's intended to provide a convenient starting point for you to create a customized list of your own.
For actual use while packing, of course, a more compact format is preferable. You can download the convenient checklist version of my list, provided in Adobe portable document format (PDF) for printing on a single letter-sized page, which can be printed on both sides, then cut in half to make two copies (this also works on A4-sized paper with just a bit of extra trimming).
The one-page checklist has been refined over many years, and changes infrequently (though the more detailed, annotated version on this Web site is updated often). If you downloaded the checklist after 2015-05-27, you have the current version.
It somehow feels beneath us to use a checklist, an embarrassment. It runs counter to deeply held beliefs about how the truly great among us — those we aspire to be — handle situations of high stakes and complexity. The truly great are daring. They improvise. They do not have protocols and checklists.
Maybe our idea of heroism needs updating.
Dr. Gawande would undoubtedly concur: the consistent use of a OneBag-style checklist is the single most important step you can take to lighten your packing load.
Keep one in your bag.
A One-Page Packing Checklist
This is a travel packing checklist, not a list of items to bring on any particular trip! Rather, it's more like a "worst-case scenario", and functions as a self-imposed constraint, a pact — made with yourself — that "if it's not on my list, I won't put it in my bag" (see: Do I Really Need a Packing List?).
If you're departing on a three-day business trip to Albuquerque, your bag might contain only a fraction of these items. If you're off on an extended trip, or to see a bit more of the real world, then more of them will be relevant; common sense should dictate. But although there will almost always be things on your list that are not in your bag (i.e., unnecessary to a specific journey), there should be nothing in your bag — or on your person — that's not on your list (this being the whole point of the list).
It's a rare trip indeed that would need every item below (all of which are discussed in detail in the annotated packing list section). But even if you do bring everything, it will still — apart from those list items that you wear (or carry on your person), and subject to the nature of any "specialty items" you believe necessary — fit in a single, carry-on-sized bag.
2 pairs trousers/skirts (shorts?)
3+ pairs socks
3+ pairs undergarments
long (lightweight) underwear
dark (cardigan) sweater
parka, coat, or equivalent
long T-shirt or sarong (nightclothes?)
necktie, scarf, shawl, hairband, bandanna
gloves / mittens
sun hat / knitted cap, hat clip
1 pair dressy shoes (laces?)
1 pair walking shoes/boots (laces?)
flip-flops or sandals
travel pack or shoulder bag
(& luggage cart?)
daypack (fanny pack? purse?)
lightweight duffel/laundry bag
luggage lock(s) (cable?)
alarm clock/watch (batteries?)
flashlight, headstrap, extra batteries (bulbs?)
knife, screwdrivers, pliers, scissors
spoon (fork? chopsticks? spork?),
(coffee tin lid) plate or bowl
safety pins, cord, fasteners
sewing kit, including large needle
to accommodate dental floss
(Ziploc®) plastic bags, garbage bags
repair tape (packing tape? glue?)
toothbrush, cap, tooth cleaner, floss
razor, blades, shaving lubricant
comb and/or hairbrush
shampoo, bar soap & container
viscose towel (washcloth?)
inflatable travel pillow
earplugs (sleep mask?)
sleep sack (sleeping bag?
bivouac sack? blanket? tent?)
(surgical latex braid) clothesline (carabiner?)
universal (flat) sink stopper
inflatable hangers [to dry clothes]
toilet paper, water squirt bottle,
(chemical or mechanical) water purifier
analgesic of choice
diarrhea treatment of choice
infection treatment of choice
insect repellent, mosquito net
sunscreen, lip balm
bandages (other first aid?)
and/or prophylactic supplies
vitamins, necessary medications
(collapsible) plastic water bottle & cup
dark glasses, retainer, case
lens cleaning cloth/supplies, copy
of prescription (spare glasses?)
pen(s), small notebook, glue stick
[for notes, addresses, diary, …]
personal address book (stamps?)
maps, guidebooks, phrase books, Post-it® notes, restaurant lists, membership cards, business/calling cards, telephone access numbers
large envelopes [to mail things home]
passport, visas, extra passport photos, vaccination certificates
copies of important documents
(international?) driver's license, health insurance information
charge & ATM cards, cash (traveller's cheques?)
2 personal cheques
security pouch [worn under clothes]
camera (lenses? flash? tripod? extra cards & batteries? charger? download adapter?)
cellular telephone (charger/adapter(s)/battery?)
travel computer (flash drive? power cord/adapter(s)? network cable(s)?)
Remember, not everything goes into your bag (e.g., listed clothing quantities include the items that you will be wearing).