Having organized numerous treks in the Himalaya, we can advise you on the optimal gear and clothing you should bring with you.
Well before your arrival in Nepal you will receive a packing list. Once in Kathmandu you will be given a trek-kit bag, which will be carried by our staff, so there is no need for giant expedition packs (unless, of course, you were looking for that kind of adventure, and do not wish to avail of the services of a porter). If you arrive with more luggage than will be taken with you on the trek, you can store it at the hotel in Kathmandu.
Due to airline restrictions on the flight to Lukla, your Everest Trek kit-bag cannot weigh more than 15kg when fully packed. While the Annapurna Circuit trek does not technically involve any airline restrictions, we similarly cap the weight at 15kg per bag, as per porters’ spinal health. These guys have to carry everything for the group, so we actively discourage unnecessary items like bowling balls and religious statues.
You will carry your own daypack, which will contain whatever personal items you need with you, plus your water, rain jacket/sweatshirt, snacks, and camera. DO bring your camera. Seriously.
While it is best to bring everything with you beforehand in order to avoid last minute shopping frenzies, there is no need for panic, as Kathmandu is a great place to pick up mountain gear. Whatever equipment was missed can be easily obtained right here, even the day before leaving for the mountains. Some gear can be rented, although we do highly recommend that items of personal use (such as sleeping bags and parkas) get purchased well beforehand, thus ensuring maximum comfort. Your boots, on the other hand, should be very well worn in so you avoid any blisters and surprises. Likewise, it is highly recommended that you form a cosy relationship with your trekking backpack long before the expedition commences which will minimize discomfort.
After two days of trekking in the Everest region we arrive in Namche Bazzar which offers additional opportunities to pick up additional items that may be deemed necessary for the optimal experience. Similarly, on the Annapurna Trek, on the 4th day or so, we arrive in the village of Chame which also has several stores selling various trekking necessities.
Obviously, it is best to have all your items lined up before your arrival in Kathmandu, and so HERE IS A LINK TO A DETAILED PACKING LIST.