Karma is something that is a continuous process and is unavoidable, while astrology is a personal preference. One has to make efforts, for example, you cannot be a doctor without the study of medicine so an uneducated won't be able to be a doctor, but who can stop him from opening up a hospital if he has the resources and will to do so. Like all other subjects, astrology has its limitations, it is not fortune-telling but a precise possibility analysis. Coming to efforts almost everyone makes an effort to study with the purpose of acquiring employment almost 80% fail to source the preferred employment and about 50% have to choose other avenues of livelihood, a skilful astrologer can guide by evaluating the possibilities but then skilful and honest astrologers are rarest of the rare, so it again rolls back to one thing if possible avoid visiting astrologers until you are satisfied with the skillset and integrity of the person involved. As regards if everything is predestined why should one make an effort, things are predestined but karma is continuous it happens automatically as an action, reaction or effort to acquire. For example, a homeless beggar sleeping on the roadside is run down by a drunk brat speeding through his new wheel ride. The beggar was sleeping at his usual place but the predestined event still took place through some other individual, the action was through the brat and the reaction is the injury or death of the beggar. No doubt we all have some free choices called free will but they are operative within the circle of destiny, destiny is based on past karmas as per our scriptures and texts. Let's talk about medicine if one has to die no medicine or care can stop the imminent death, so as per your thinking process why should one take recourse in medicine for physical suffering, we all know and accept the limitation of medicine but when we talk about astrology we don't even think about the possibility of its scope, purpose and limitations, agreed that 90% of the astrologers are without any skill set or are dishonest, remedies specifically related to recitation and donation are for the mind they may help the mind to understand or to optimise the decisions subject to the conditions and circumstances at hand but remedies of any sort have no power to alter or avert. Now a question may arise as to why a certain remedy as named by me recitation or donation may stabilise a mind the reason is the conditioning we receive right from birth that God is omnipotent which actually is true as per the scriptures, evidence and reality so when we recite or donate we feel better as related to mind and it may help the individual facing a certain challenge or situation.