It is Mustahab (recommended) for persons who are not able to perform Hajj or do not have other conditions or have performed obligatory Hajj, to perform Hajj and it is Mustahab to perform it every year. But if due to extreme congestion of Hajjis there is a interruption for people who have not performed their obligatory Hajj yet, then it is preferred not to perform Mustahab Hajj.
It is also preferred to give turns to persons who have not performed obligatory Hajj and want to perform for the first time; but if (assumably) the house of Allah has enough places remaining for Hajjis for one year then it is obligatory for the religious governor to send groups of people for performing Hajj even if they have already performed their obligatory Hajj.
Permission of the husband is not necessary for the wife to perform obligatory Hajj, but the permission is necessary when wife wants to perform Mustahab Hajj. Also if Mustahab Hajj is bringing hardship and hurt to father or mother then there is a problem.