Communication and visitations-Staying in touch with one’s parents:
A. Living near one’s parents:
It is proper for one to live near his parents in order so one can properly honor them and help them with their needs. This especially applies once parents are old. Nonetheless, this is not necessarily an obligation and it all depends on the circumstance of the child and parent and the reasons for not living in the same area as the parent [i.e. Chinuch, cheaper housing, marriage].
B. Being in contact with one’s parent if one lives far away:
In the event that the child lives far away from the parent, then he is obligated to be in contact with them either through telephone or writing to seek their welfare and to inform them of his well-being. This applies even if communication is expensive from one’s area of living nevertheless, he must cover the costs. The frequency of this communication is all dependent on the norm for one’s society in the relationship of a parent and child. It also depends on whether the parents made a specific request of the frequency of communication.
C. Being in contact with one’s parent after escaping a worrisome situation:
If one was in a state of danger, then he must inform his parents as soon as he escapes the danger. [Accordingly, upon arrival to one’s destination after a long trip, one should contact his parents to let them know that they arrived safely.]
D. Visiting one’s parents on occasion:
It is a mitzvah for one to visit his parents on occasion and whoever increases in doing so is praised.
The frequency of the visitations: The frequency of the visitations is all dependent on the norm for one’s society in the relationship of a parent and child, and the distance apart that they live as well as the physical needs of the parents. It also depends on whether the parents made a specific request of the frequency of the visitation. Some Poskim rule that if the travel will cause one to nullify Torah study, then he is not required to make the visitation.
Who pays for the traveling expenses: One must cover the expenses of traveling to his parents if he lives walking distance from them. If, however, he lives beyond walking distance, then he may ask his parents to cover his traveling expenses.
 Pesakim Uteshuvos 240:15
 See Michaber Y.D. 239:8, based on Teshuvos Harashba Meyuchasos Leramban 272, “If one swore to live by his wife’s family, then even though that by doing so he will nullify honoring his father and mother, it is not considered that he is swearing to nullify a Mitzvah of the Torah”; Binyamon Zev 281; Maharam Shick Y.D. 208; Megillah 17a that Yaakov Avinu was punished for the 22 years that he was away from home; Minhagei Maharil Likkutim Tzadik; Avnei Nezer O.C. 535:11 “From the above we learn that ideally one is to live next to his parents in order to serve them”; Meiah Shearim 16; Ish Matzliach Y.D. 1:30; Lehoros Nasan 5:53-7; Pesakim Uteshuvos 240:15 footnote 128
 See Igros Rav Akiva Eiger Igeres 92 “Why is it my son that you are lazy in the fulfillment of the Mitzvah of honoring your parents by abstaining from writing to us a few lines of how you were doing”; Yeshuos Malko O.C. 14; Teshuvos Vehanhagos 3:286; Lehoros Nasan 5:53-7; Pesakim Uteshuvos 240:15
 Sefer Chassidim 575
 See Admur 613:8 “One who travels to receive the face of his father or teacher… since he is going for the sake of a mitzvah”; Michaber 613:5; Yuma 77b; M”B 301:10; Divrei Malkiel 2:75; Meiah Shearim 17; Yehuda Ya’aleh Y.D. 310; Hisorerus Teshuvah 4 Y.D. 9; Har Tzevi Y.D. 191; Teshuvos Vehanhagos 2:444; Nishmas Avraham Y.D. p. 150; Pesakim Uteshuvos 240:15
 Machaneh Chaim 1:85
 Har Tzevi Y.D. 191 and Teshuvos Vehanhagos 2:444 in name of Rav Chaim of Brisk who when asked this question replied that since the son is able to walk to his parents’ home, the expenses of travel are not considered an expense on the side of his parents, but rather an expense of his own to ease his journey; Nishmas Avraham Y.D. p. 150 in name of Rav SZ”A that if he does not live walking distance from his parents then his parents may be asked to cover the traveling expenses, of the cheapest form of travel.