Himalaya Trekking in Nepal is best to take only what you need and leave the rest behind. You need while trekking will be simple. It is possible to buy or rent everything you need in the Thamel neighborhood of Kathmandu and Pokhara, although it is better to use footwear that is already broken in. Good bargains can be had on fleeces and down jackets but the knockoffs of brand name goods sold in Nepal is not good quality.
The main essentials to bring are sturdy and comfortable hiking boots, a sleeping bag depending on your accommodation, a day pack, and a few changes of clothes for the varying temperatures. For cold weather, trekking pants, thermals, gloves, neck warmer/scarf, beanie, a warm inner jacket and a windproof/waterproof outer jacket are essential. Other items to bring include a walking pole or two, waterproof case, fabric bandages such as moleskin, a headlamp, water purification supplies, altitude sickness and other medication, a camera, and binoculars.