Answered by Shaykh Abu Usamah
Tawaf al-Ifada, also known as Tawaf al-Ziyara is one of the fundamentals (arkan) of Hajj. Without performing this tawaf the Hajj remains incomplete.
In the reliable books of Fiqh such as Bada’i` al-Sana’i`; Fatawa Hindiyya; Radd al-Muhtar etc., it is stated that this tawaf will never be waived and remains incumbent to perform even after returning home. Thus a person who returns home without having performed this tawaf will remain in the state of Ihram (i.e. sexual relations are prohibited) and must return to Makka to fulfill this tawaf. In addition a penalty (of a sacrificial animal) is also necessary for the delay in performing this Tawaf and another for the omitting of Tawaf al-Wada.
However, if the person had performed any other tawaf (e.g. Tawaf al-Sadr also known as Tawaf al-Wada`) after the Wuquf at `Arafa then this tawaf will take the place of Tawaf al-Ziyara and a penalty (of a sacrificial animal) is necessary for the omitting of Tawaf al-Wada`.
(References: Bada’i` al-Sana’i` 2.133; Fatawa Hindiyya 1.246; Radd al-Muhtar 2.552)
Allah Ta`ala knows best.