Above Namche: awareness of the time taken for the body to acclimatise is the key to planning itineraries in the Khumbu.  The usually ignored medical recommendation is that a minimum of 2-3 days should be taken to reach 3,000m/10,000ft, followed by a daily altitude gain of 300m/1,000ft with a rest day every 900m/3,000ft.  On acclimatisation days, it is popular to climb to a higher elevation only to return to the lower elevation to spend the night.  We climbed above Namche to Khumjung (3,790m/12,434ft) and I took this picture as we came back down.