Historically several Grimoires require priests to perform consecration or pray for the magician. But is it really necessary to find a priest to do these things for you? Before we can answer this, we need to look at the historical lineage of particular texts. For example the Key of Solomon does not appear to require a priest for anything. It has its own way of making holy water and consecrating all of its tools independently. There is however another line of magic which parallels and predates the key that historically depends on priests to do certain things (that is up until the Protestant reformation), that of the Heptameron and its predecessor the Elucidarium and Liber Juratus.
Then he should have a cautious and faithful priest, who should sing for him Matins, Prime, Terce, and a Mass fo the Holy Spirit.Liber Juratus (Peterson)
Here we see in Liber Juratus (1320’ish) it is necessary for the magician to find a priest who can pray over him for success and modify a Mass of the Holy Ghost with prayers form the text. A little later we see the emergence of the Elucidarium (around 1480 or so) where a priest is needed to bless the perfumes and say a Mass of the Holy Ghost over the tools. About 100 years later we see the Heptameron emerge in the Fourth Book of Occult Philosophy which requires obtaining holy water blessed by a priest. So we have set a baseline in this line of magic requiring a priest though to different extents. If you are practicing Liber Juratus or the Elucidarium, yes a priest will be required to different extents. But what of the Heptameron? Well, there is some contradiction here as it states you need holy water from a priest, but the Fourth Book of Occult Philosophy (which contains the Heptameron) says otherwise.
By the time we reach the Heptameron we have spanned nearly 250 years since Juratus and the requirement for a priest (though still present) is a lot less involved. In fact the Fourth Book of Occult Philosophy was first printed at a press available at the first Protestant Collage and the works favor of Protestantism does manifest from time to time including the chapter on consecration which states some radical ideas about the role of the priest in consecration.
And now we come to treat of the Consecrations which, men ought to make upon all instruments and things necessary to be used in this Art: and the vertue of this Consecration most chiefly consists in two things; to wit, in the power of the person consecrating, and by the vertue of the prayer by which the Consecration is made. For in the person consecrating, there is required holiness of Life, and power of sanctifying: both which are acquired by Dignification and Initiation. And that the person himself should with a firm and undoubted faith believe the vertue, power, and efficacie hereof. And then in the Prayer it self by which this Consecration is made, there is required the like holiness; which either solely consisteth in the prayer it self, as, if it be by divine inspiration ordained to this purpose, such as we have in many places of the holy Bible; or that it be hereunto instituted through the power of the Holy Spirit, in the ordination of the Church.Fourth Book of Occult Philosophy
Donald Tyson’s commentary on the matter clarifies that the most obvious candidate is a priest, but that is not necessarily the case. Regardless if the person doing the consecration is a priest or not, a person who has “holiness of life and power”, who has “undoubted faith”, etc is indeed required. While this does mean a priest is not required it does indicate that not all magicians meet the requirement either. The Fourth Book of Occult Philosophy (which contains the Heptameron) therefore dignifies the person consecrating to be of merit which is not held to the magician.
It also makes a distinction between magical things which the magician will do and priestly things which the priest / other qualified person will do. This directs us to the next point I want to make which is magical timing for consecration. Knowing prior to the Fourth Book (1559) a priest was indeed required. Consecration was done by Mass of the Holy Ghost and other blessings (holy water, perfumes, etc). The Church did not operate by observation of day and hour and lunar phase. Which means the consecration of the pentacle which requires a mass of the Holy Ghost was not necessarily done on the day and hour of mercury during a waxing moon. Rather it was done by the standards of the Church. This means that the creation of tools such as the pentacle or sword are observed by typical Solomonic observation of lunar phase, day and hour but consecration was done separately and by another individual all together. While the Fourth Book does not require a priest for consecration it does distinguish a difference between priestly tasks (such as consecration) from magical tasks (ritual tool construction). Therefore if a magician chooses to make their own tools and consecrate them, they need not observe the same set of requirements in consecration as they do in ritual construction (though there would be no harm in aligning them).