How long should the right planning time be?

As the basic groundwork for engaging in a long walk is completed, I mean when the balance between knowledge of the task and the mistery of it has reached the sweet spot, then it should be pretty much the date of departure.

If not, a painstaking process gets immediately on the way, conjuring against your still precarious decision balance. This comes in from various sources: either from people that want to to join you, it people that say it us totally useless, or too commercial, from the agony of fear of unplanned discomfort, of not being physically fit, of missing the single fundamental item that will turn the experience from barely bearable into a total hell.