The point thseng touches upon is important.

As a backpacker, I make a conscious decision to head off into the wilderness (or perhaps the not-so-distant trail) having prepared in advance to take care of myself over a period of time. Barring sudden accidents and unexpected events, one would assume that I have prepared water, shelter and food for the length of time I plan to spend hiking, I am familiar with the terrain, I have made allowances back home for my absence etc.

On the other hand, I often mix my every day carry with the extra and specialised items I would only use when spending nights outside. Similarly, I often carry a couple of lightweight items if I am merely hiking, just in the event that the weather turns or I am forced to overnight.

I'll post some pictures in another thread to illustrate what I mean.