As has already been stated, there are thirteen obligations in Hajj. These will now be dealt with in some detail:
The best time for wearing ihram for Hajj is the day of Tarwiyah which is the eighth of Thil Hijjah at zawaal. It is permissible for old and sick people who are fearful of overcrowding, to wear ihram, three days before then. They can wear ihram and leave Makkah before other people. Indeed, if need be, they can leave immediately after completing Umrat-ut-Tamatu'.
Similarly, it is permissible for those permitted to perform tawaf of Hajj before wuquf at Arafat and Muzdalifah, to wear ihram earlier, such as a lady fearing the onset of haydh. As has already been discussed, it is permissible to wear ihram for Hajj and leave Makkah, for a legitimate business, at any time, after completing Umrat-u-Tamatu'.
Evidently, it is also permissible to wear ihram, three days earlier than should be the case, and even earlier than that in certain circumstances.
Rule 358: As has already been discussed, it is not permissible for a pilgrim performing Umrat-ut-Tamatu' to wear ihram for Hajj before taqseer. So is the case in Umrat-ul-Mufradah before completing the ceremonies of Hajj. However, it can be worn after completion of all the ceremonies, but before Tawaf-un-Nisa.
Rule 359: Whoever can make the wuquf at Arafat on the specific day and time, it is not permissible for them to delay putting the ihram on until such a time when it becomes untenable.
Rule 360: The rules governing the procedures, obligations and prohibitions of a state of ihram apply just as those governing both ihram for Umrah and Hajj. The only difference between them is in the niyyah
Rule 361: It is obligatory to wear ihram from Makkah as mentioned above. The best place for it is the Holy Mosque. It is recommended to wear the ihram after performing two raka'as of prayer at Maqam Ibrahim (a.s.) or Hijr Ismail (a.s.).
Rule 362: A pilgrim may forget to wear ihram, either inadvertently or because of ignorance of the rules, until he has left Makkah. If he remembers or becomes aware of the rules at a later time, it is obligatory on him to return to Makkah, even if he is in Arafat; he should wear ihram from there.
If because of limited time, or for another reason, it is not possible to return to Makkah, he should wear ihram wherever he is. Similarly, if he remembers or becomes aware after the wuquf at Arafat, he should proceed to Makkah, where possible, and wear ihram there. However, if he does not remember or acquire the knowledge until after completing Hajj, his Hajj is valid.
Rule 363: If a pilgrim knowingly and deliberately fails to wear ihram, it is obligatory on him to rectify it. Should it not be possible to do so before the stay at Arafat, his Hajj is invalidated and he is obligated to repeat it in the following year.
Rule 364: One must, as a matter of precaution, one make an optional tawaf after wearing ihram for Hajj and before departing from Makkah. If one does so, one must, as a matter of precaution, renew the talbiyah after tawaf.