I have to admit I do get a bit depressed at times and you know I think about the good old days when I was charging ahead.

Motivation is the single most important factor in any sort of success.

Mount Everest, you beat me the first time, but I'll beat you the next time because you've grown all you are going to grow... but I'm still growing!

June [Hillary] is a very strong influence in my life and particularly now in my ancient years there is no doubt at all: if there's a decision to be made, quite often June is the one who makes it.

While on top of Everest, I looked across the valley towards the great peak Makalu and mentally worked out a route about how it could be climbed. It showed me that even though I was standing on top of the world, it wasn't the end of everything. I was still looking beyond to other interesting challenges.

I have the challenges sort of already there and as a consequence my companions feel a considerable desire to do this, too, and they feel very put out if they are left in the cold, so there we have it. We have me who has lots of ideas and then we have a very good team who wish - who are persuaded almost - to take part in these challenges.

Good planning is important. I've also regarded a sense of humor as one of the most important things on a big expedition. When you're in a difficult or dangerous situation, or when you're depressed about the chances of success, someone who can make you laugh eases the tension.