Is Acclimatisation required for Everest Base Camp Trek?

Question

What was the occupation of Edmund Hilary, the first man (with Sherpa Tenzing Norgay) to reach the summit of Mt Everest in 1953?

Answer 1

Ideally yes (not sure about the legal part of it)

Recent research suggests that you will need more time to adjust to the lack of oxygen at 3,500m/ 11,500ft. Adjusting and acclimatizing needs time. If you fail to acclimatize well lower down you will really struggle higher up. So the closest town at this height is Namche Bazaar 3,440m/ 11,286f, may be spend three to four night at this height which is critical for your safety moving higher.