Our first trip to Kathmandu is now over, so there are some lessons learned I should scribe. Some of these are obvious, and which we abide by whenever travelling, and some we simply forgot in our (very) impromptu trip to Nepal.
1) When agreeing on a price, make 100% sure the other person states the price back to you. I thought a price had been agreed to when the other person responded "ok ok, you are a lucky man", but this does not count. As they say, reconfirm, reconfirm, reconfirm.
2) When arriving at the airport, make sure you have small bills, too. We had 3x 100RS, 1x 10RS, and then a few 500RS. The price we negotiated was 440RS, and it would have been nice to have paid the exact amount.
3) Kathmandu is polluted and dirty. I cannot emphasise this enough. It is dirtier than probably any other city we have been to. If we come back, we will be bringing masks. I know this sounds silly, to wear a mask, but any local on a motorbike or in a taxi wears a mask, and many just walking around. Instead of the normal cloth masks that many people use, I would probably bring a make with finer grained material (maybe not N95 quality), and something with activated carbon. I'd probably get a mask like one of these. We ultimately tried to avoid walking on main roads, but having some activated carbon absorb something would have made it a little less unpleasant.
4) My wife's tip: bring dirty cloths, and throw them away after the trip. Or just bring black. Her beautiful blue jacket is now pretty filthy, with grease covering parts of it.
5) Bring some toilet paper. Similar to other parts of Asia, the bathrooms don't have any.
6) Bring a flashlight. The load shedding makes the city dark, and if you go out, you will want a flashlight. There aren't any lights. We only used it a few times, but I am really glad we brought two flashlights with us.
7) Bring vitamin C and lots of hand sanitizer. We did, like we always do when we travel, and I'm really glad we did. Everybody is coughing or sick, and everybody spits. It is similar to the situation in China, i.e. everyone spits. Then everybody gets sick. Bring hand sanitizer.
8) If you take a bus somewhere, try to ask when you buy tickets to sit on the left side in the middle. The front is a no-go for me. We typically had seats in the rear right, but on the curvy roads I think the left middle would be safer, as oncoming buses won't hit you. One bus on the way back had the left side decimated. If you do a search on "nepal bus crashes" in images.google.com, you will quickly see why you don't want to be in the front row.
9) Our hotel rooms all typically had just one power outlet. If you bring multiple electronic devices, bring some way to charge more than one at a time. Something like like this travel charger would work well.
10) Bring clothing to stay warm at night. We travelled to Nepal in winter, and all our rooms got pretty cold at night.