Most foreign tourists to Nepal are there for the trekking. Many will go in organised groups led by a major company. This is perhaps the ' safest ' way but costs much more. A major disadvantage to walking in a group is the peer pressure you can feel under if ill ... and the consequences of not listening to your body if you feel the symptoms of altitude sickness ( see Medical ) can, quite simply, be fatal.
In Kathmandu and major trekking centres there is a plethora of trekking agencies - no problem finding a guide and/or porter but the difficulty is knowing which might be good. As in 2008 we chose Nature Trail based in Thamel, Kathmandu and cannot speak highly enough again of the thoroughness and quality of good value service we received. Once again Kharma, our guide, and Nima, our porter, became good friends and we remain in contact.
Finally, of course, you can opt to do everything yourself - the cheapest solution! However, you miss the insights in to local life provided by good guides, the value of their Nepali language and above all the opportunity to support the impoverished local economy. As our friends said: ' There's only one thing worse than employing a guide and porter ... and that is not employing them! '