I write from direct experience.
The square of Saturn, performed when this planet is retrograde, can bring about a temporary and fast reduction and restriction of many of our intrinsic faculties. Before delving into this work, I had performed its square several times while Saturn was in direct motion, and although I always obtained benefits and only rarely a few negative effects, I consistently noticed very firm and “immediate” energies.
However, when I performed the square for the first time while Saturn was retrograde, I experienced very serious difficulties and challenges, partly connected to the domain of this planet, all of which manifested on my inner and introspective plane. I found it very hard to handle and to gather my strength and willpower to bring it to completion and, when I reached the final day, the difficulties, which, in my case, took the form of the forced removal of certain inner patterns, reached their peak, and I was on the verge of giving up. Even though that day’s repetition was only one, my mind devised every kind of self-sabotage and stratagem to prevent me from finishing the work.
I can only share my own experience, which was deeply internal and introspective; on the external/material level, I did not encounter particular difficulties. This, of course, depends on many factors. In any case, to carry out this kind of square, one must be aware of why one is doing it, and not merely do it just to “try something out”. To be aware of why one wishes to undertake a particular work means having examined oneself and understood what one’s soul needs in order to grow, to heal, to become stronger, or to be freed. It means having acted introspectively upon oneself, engaging in self-evaluation.
Moreover, if it is necessary for the soul, your Guardian will lead you to this choice. Before experimentally performing any magical work or meditation (not only in the Saturn square) whose effects you cannot foresee, or when you are unsure whether it is truly right for your soul, I strongly recommend turning to your Guardian first who is the only one that can offer to you a proper guidance for your advancement.