Praise be to Allah.
Firstly: the hair on the arms and legs is something about which sharee’ah does not say anything. If sharee’ah does not say anything about a matter, it is allowable. It does not come under the same heading as the hair which we are commanded or recommended to remove, and it does not come under the heading of the hair which we commanded to leave alone – such as the hair on a woman’s head and the eyebrows.
Because sharee’ah does not say anything about it, the scholars differed concerning it. Some of them said that it is not permissible to remove it, because removing it is changing the creation of Allaah, and Allaah tells us that the Shaytaan said:
“ ‘and indeed I will order them to change the nature created by Allaah’”
[al-Nisa’ 4:119 – interpretation of the meaning]
Others said that it is permissible to remove it because it is one of the things concerning which sharee’ah did not say anything, so the ruling is that it is permissible, since whatever sharee’ah did not say anything about in the Qur’aan or Sunnah is allowable, as it says in the hadeeth: “What is halaal is that which Allaah has permitted in His Book, and what is haraam is that which Allaah has forbidden in His Book, and whatever He has not said anything about is allowable.” Narrated by al-Tirmidhi, 1726; classed as hasan by al-Albaani in Saheeh al-Tirmidhi.
The view that it is permitted is the view favoured by the Standing Committee, and also by Shaykh Ibn ‘Uthaymeen. See Fataawa al-Mar’ah al-Muslimah, 3/879; Majmoo’ Fataawa Ibn ‘Uthaymeen, 11/q. 64.
Secondly: It is mustahabb for husband and wife to make themselves look good for one another, because Allaah says (interpretation of the meaning):
“and live with them honourably”
“And they (women) have rights similar (to those of their husbands) over them to what is reasonable”
It is customary for spouses to make themselves look good for one another. If the husband tells his wife to make herself look good for him, then it becomes obligatory for her to do so, because that is his right and because obeying the husband in that which is good and proper is obligatory for her. Al-Mawsoo’ah al-Fiqhiyyah, maadat al-tazayyun, 11/271.
Based on this, if the husband tells his wife to remove the hair on her arms and legs, and that will not cause her any harm or involve her doing something haraam, then it is obligatory for her to do that. The husband should forego his right to ask his wife to do that if she convinces him that this causes her hardship or she does not want to do it and so on.
Thirdly: with regard to going to a salon to do this, there is nothing wrong with that, so long as the following conditions are met:
1-That should be done by a woman, with no men present. The place should also be one where the people can be trusted, especially nowadays when cameras etc are readily available and many people are corrupt.
2-The women should not see any part of her ‘awrah such as the thighs. It should be limited only to the arms and lower legs as Shaykh al-‘Uthaymeen said (al-Liqa’ al-Shahri, q. 278)
3-The salon should not be a place where ‘awrahs are uncovered. The scholars have stated that it is haraam for a woman to enter public baths because they are places where ‘awrahs are uncovered. Al-Albaani (may Allaah have mercy on him) said: The public baths are definitely haraam for women. It was narrated that Abu Maleeh said: Some women from Syria entered upon ‘Aa’ishah (may Allaah be pleased with her) and she said: “Who are you?” They said: “From the people of Syria.” She said: “Perhaps you are from al-Koorah where women enter the public baths?” They said: “Yes.” She said: “I heard the Prophet (peace and blessings of Allaah be upon him) say: ‘There is no woman who takes off her clothes anywhere but in her own house, but she has torn (the veil of modesty) between her and Allaah.’” Narrated by the authors of the four Sunans, and its isnaad is saheeh according to the conditions of al-Saheehayn. Tamaam al-Minnah 130).
And Allaah knows best.