There is a main point to be impressed, a kind of "rule of thumb," for those who head out into the spiritual desert, also as a lived experience. Examples and thoughts gleaned from lived experience and much reading the lives of historical and holy hermits, saints, and mystics, plus the Biblical prophets, apostles, and life of Jesus--come to a basic consideration.
A person casts out into the deep, sets off for the "desert", does so because His Real Presence has placed a desire within the soul, or has called the person through discerned circumstances and/or through inner voice or nudge.
The rule of thumb as far as how or when--radical or extreme conversion or turning away from what was of one's life to whatever God asks of the body, mind, heart and soul--all depends upon His Real Presence.
Yes, the point to be impressed is that God must be the one who beckons. God must be the one who leads. God must be the one who determines how much to detach, when, and to what degree. And God does this through preparing the soul to be able to do His will in this regard of leaving all at once or in degrees, and to what extent with what purpose. He knows each soul and what each soul can reasonably offer of itself, depending upon its growth in virtues and depth of love of His Real Presence.
All we have to do is be willing. Make the initial offer and repeat that offer if we do not discover the answers right away. The answers will come, and we will find ourselves being extricated all at once or little by little (and usually the latter, it seems), and going out farther into the desert, detaching from the hindering effects of the temporal world, by and by, yet always and only by God's allowing and guiding and providing.
The pathway to union with God always traverses a desert of one sort or another, or many deserts with rest stops along the way. Sometimes God asks of the soul to travel without much stopping, and to detach from hindrances in a full swoop of the axe. Such was the call for Antony of the Desert, for Mary of Egypt and Pelagia, and many others. Most go through a less severe pruning and are pruned of hindrances (possessions of temporal and spiritual passions) much like one would a Japanese Maple, in tiny bits to shape its form over time.
The main point, the rule of thumb, though, simply put: God inspires, speaks, calls, leads and determines the details...every step of the way.
God bless His Real Presence in us! Little children, let us love one another in our lives and love of God!