Siman 251

We say at the beginning of "Makom She-nahagu" (Pesachim 50b): One who performs work on Erev Shabbat from mincha and onwards does not see a sign of blessing from this work. Nevertheless, we do not punish him, but we warn him not to do so. There are those who explain this as mincha gedola, which is half an hour after midday, and there are those who explain this as mincha ketana, which is from nine hours and onwards, and such is the primary ruling. (Taz and Magen Avraham; and the Taz and the Bach labored according to this to explain the difficulty of the Gemara there, "why specifically Erev Pesach etc.", and they did not see the words of the Ran there who explained it very well, see there)

Specifically labor, but business—is permitted, and likewise sitting in a shop. And likewise, labor is specifically when one performs it in a permanent manner, but if one performs it in a temporary manner for the moment, and does not establish it—it is permitted, and therefore it is permitted to write letters of greeting and anything similar to this. And likewise, to repair his garments and his vessels on Erev Shabbat for the sake of Shabbat—is permitted the entire day, and the same law applies to the garments of his fellow for the sake of Shabbat, if he does not take payment for this. And if he is a poor person and wants to spend the payment for the honor of Shabbat—it is also permitted (Taz subsection 2), and the same law applies to one who writes books for himself in the course of his study. And all the more so to write novellae of Torah—as it is permitted the entire day, but to write for his fellow for payment—is forbidden as with all labors.

And one may cut hair the entire day, even if an Israelite cuts it, and even professional work, and even for a fee, since it is for the honor of Shabbat and it is evident to all that it is for the honor of Shabbat, and it is not similar to the repairing of garments that was explained (Magen Avraham, subsection 5). And all the more so the trimming of nails, which is permitted the entire day. The Arizal was careful not to shave after Mincha on Erev Shabbat, and all the more so on a weekday, for the reason that he had not yet prayed Mincha, and according to the system of the Rif and the Rambam in siman 232, see there (see Magen Avraham ibid. and Eliyah Rabbah). And there is one who hesitates based on the law of melacha itself on Erev Shabbat after the time of Mincha, not to shave after midday (see Biur HaGra), but the world does not practice accordingly. Our teacher, the Rema, wrote: A person should diminish his study a bit in order to prepare the needs of Shabbat. Thus far his words. Therefore, if his wife prepares on his behalf, he should not diminish his study (see Magen Avraham subsection 6, it requires further study), and regarding the nullification of Torah study one must deliberate greatly, and especially nowadays when craftsmen do not nullify their work—all the more so the study of Torah, "If not for My covenant," etc.

And one must wonder why in our time the craftsmen do not cease their work until close to sunset, and we have never heard of anyone protesting against them; perhaps this is due to the pressure of earning a livelihood. Furthermore, it can be said that in Hoshen Mishpat, siman 331, it is explained that a worker performs his work for the employer until close to sunset, in order to roast a small fish for him, see there, and this is according to the Yerushalmi. If so, the law of ceasing work applies only to the employer and not to the workers, and nowadays most craftsmen have workers and they are the ones who work. Furthermore, it can be said that they do not perform new work but rather finish some work, which is more lenient. Furthermore, it can be said that the reason for ceasing work is because one must prepare for Shabbat, and nowadays the women prepare everything. So it appears to my humble opinion to find merit, and one who fears G-d will act according to the enactment of the sages and it will be well for him.