On longer trips you have to resupply. I find it makes a huge difference if you go back out to civilization to resupply or have a wilderness resupply (ie: commercial outfitter resupply). If you read the PCT journals you soon realize that except for a few longer stretches they mostly come out to civilization every few days.

My longest time out without contacting civilization is 35 days. I was not solo - rather with a large group (NOLS courses). Some people never get really comfortable outdoors, but most need 2 weeks to quit thinking of "when I get out" and just live day-to-day with your tent being your psychological "home".

My longest time out solo, without seeing another person was 8 days. This is another entirely different experience.

Either case, the more time I am out, the less I want to go back to civilization-- that is, until winter sets in! Then I am fully aware of my preference for a few more creature comforts.