There is nothing wrong with singling out Saturdays for family visits
Question

                We live in the west, and my wife’s family also live in the same city as we do. We always go to visit my wife’s family on Saturdays. My wife has married sisters who also live in the same city, but my wife and her sisters have set aside a day to visit their family, which is Saturday. I told my wife off for that, and said to her, “Why Saturday? Because it is the day of rest for the Jews, and we do not want to imitate the Jews.” But she said to me that the children have two days off in the week, Saturday and Sunday. I said to her: Why don’t you go on Friday, or sometimes on Friday and sometimes on Saturday, or any other day? But my wife is not convinced of that. I hope that you can answer this, may Allaah reward you with good. Please note that my wife goes to her family whenever she wants, but she and her sisters still go on Saturdays.
Praise be to Allah.First of all, we ask Allaah 
    to reward you with good for your keenness to avoid following the ways of the 
    disbelievers, and your fear of imitating them. This is how the believer is; 
    he is proud of his faith and his Islam, and he does not agree to be a blind 
    follower of those with whom Allaah is angry among the Jews and Christians. 
But there is nothing wrong 
    with what your wife and her sisters are doing, as it seems to us. It is not 
    the haraam kind of imitation, in sha Allaah, because setting aside Saturday 
    for visits is not because it is a special day, rather it is because this is 
    easier for them and is more suited to the family’s circumstances, as it is 
    possible for everyone, because of this day off, to visit. Shaykh al-Islam 
    Ibn Taymiyah (may Allaah have mercy on him) said: 
With regard to the one who 
    does something and it so happens that others do it too, and one of them did 
    not copy the other, then the question of whether this is an imitation or 
    not  is subject to further discussion. End quote. 
Iqtida’ al-Siraat 
    al-Mustaqeem (p. 82) 
He also said: 
That which is not 
    originally taken from them, but they do it too, does not come under the 
    prohibition on imitating them, but it may mean missing out on the benefits 
    of being different. Whether it is makrooh or haraam depends on shar’i 
    evidence as to whether it is imitating them, because we cannot say that we 
    are imitating them, rather it may be said that they are imitating us. End 
    quote. 
Iqtida’ al-Siraat 
    al-Mustaqeem (p. 223) 
From the words of Ibn 
    Taymiyah quoted above about the guidelines on what is the haraam kind of 
    imitation or resemblance, it may be understood that your wife and her 
    sisters setting aside Saturday for their visits is not haraam according to 
    sharee’ah, for several reasons: 

    1.Visiting relatives is 
    prescribed in our religion at all times, and it is the practice of our 
    Prophet  (peace and blessings of Allaah be upon him) and of our 
    righteous forbears at all times and in all places. There is nothing wrong 
    with singling any day out for that, according to circumstances and time. 
    This is according to scholarly consensus. 

    2. Visiting people on Saturdays 
    is not one of the unique characteristics of the Jews and Christians, and it 
    is not something that has been adopted from them. Rather it is something 
    that all people have in common, and is not unique to one nation rather than 
    another. Rather what is unique to the Jews is taking Saturday as a holy day 
    on which the people show the outward manifestations of it being a holy day, 
    that they do not do on other days.
In the answers to questions 
    no. 21694 and 
    108996 we have mentioned some of the guidelines on the 
    imitation of others that is haraam. 
As it does not seem that 
    this action of theirs is imitation of the kuffaar, and there is no fear that 
    they may do that, then there is nothing wrong with their singling out 
    Saturdays for such visits, if that is easiest for them and most suited to 
    their circumstances. 
Al-Bukhaari (1193) and 
    Muslim (1399) narrated from ‘Abd-Allaah ibn Dinar that Ibn ‘Umar (may Allaah 
    be pleased with him) used to go to Quba’ every Saturday and he used to say: 
    I saw the Messenger of Allaah  (peace and blessings of Allaah be upon 
    him) coming to it every Saturday. 
To sum up: If singling out 
    Saturdays for visits is easier for them, then there is nothing wrong with 
    it, in sha Allaah, and it does not seem that there is anything wrong with 
    it. If their circumstances allow them to choose another day, other than 
    Saturday or Sunday, or they can switch it every time, that is more on the 
    safe side for them and further removed from imitation of the kuffaar, and is more obviously being different from the kuffaar in their festivals and special days. 
And Allaah knows best.