What are your tips for onebag travel?

Heh, what a niche community to stumble across! My wife and I have been nomads with one bag each since 2016, with a 2-year break whilst lockdowns were a thing. Started with 10kg bags, but post-pandemic all the airlines are 7kg max for free carry-on, so we've downsized. This has meant some further weight-saving changes:

• A very light canvas bag! Less pockets, less zips, etc.. more weight for what goes in the bag. We got the Decathlon 25L forclaz. Only one zip, but has a sleeve for laptop, and three extra slip pockets (one takes my umbrella, another my water bottle, and the front one paperwork).
• Zip-off quick-dry cargo pants with zip-up pockets. I have two pairs (again from Decathlon). Don't need separate shorts or swimming trunks. Zip-up pockets keep everything safe in crowded areas, no need for a day bag/bum bag/sling bag. When combined with thermals gives great protection from the cold, and can't be pierced by mosquitos when in the tropics.
• Clothing is 2 zip-off trousers, 8 underpants, 5 pair matching socks, 4 t-shirts, 1 shirt, 1 pair thermals, 1 pair wool gloves, beanie, and my kick-ass waterproof, lined-coat with hood (from Workman, Japan - great sturdy, but light-weight stuff). Do proper laundry once a week wearing trousers on rotation, each shirt/socks twice... unless in the tropics, then I can (and have to) wash things every day.. just in the sink and hang up to dry, then still do a proper wash once a week to get them nice and clean. My wife has three less shirts, replaced with dresses.
• USB-C everything. No need for bulky power bricks and extra cables. Phones, laptops, even my shaver... except I got rid of my electric shaver since downsizing to on weight (using disposable instead - wish I could take safety razor on planes!)
• I got rid of my packing cubes and my wife went down to just one packing cube. We now just properly unpack our clothes at each accommodation. We try to spend at least a week at each stop (for the discounts!), so not a pain.
• A zip-up flannel. This is what we keep our toiletries in... and also works as a flannel if we need one (like to make an ice bag for an injury, or clean up a mess (thanks random bird in Amsterdam!)

Hong Kong Disneyland survival gear in middle of hot+humid summer

• Evergoods MHP sling+hip pack
• Bedrock sandals
• Tenugui/japanese cotton thin+light wash cloth or it's HK equivalent.

• Soap is always tricky for me. I’ve recently been using Dr Bronner’s. It’s fairly concentrated and a travel-sized bottle covers my showering needs as well as my laundry. The incredibly minor thing I don’t like is that it’s a liquid soap, which is a small chore I have to handle when going through airport security.
• Packing cubes are fantastic. They help bring a sense of order to a 35L bag.
• Practice. I choose random weekends to pack my 1 bag and live out of it. It really helps build confidence in what you’re choosing to pack.

I’ve been traveling with one bag for years, sometimes for multiple months at a time, ranging from tropical islands to the arctic. Some quick tips:

• Pack light. If you cannot carry your full one bag for a day out in a foreign city, you’ve packed too much
• Have your bag with you. Don’t check it in while flying, don’t leave it in a hotel or a train station locker if you can avoid it
• You can do laundry while traveling. Sink wash, use a laundromat, etc
• Layering is key in cold or variable climates
• You generally don’t need fancy gear to onebag, but for example merino is quite practical
• Keep track of what you pack (lighterpack is a great website for doing this). Refine, eliminate, consider what worked and what didn’t

What do you mean by Zero drop shoes?