How does one pray the regular Sunnah prayers (Rawatib) and supererogatory prayers (Nawafil) when shortening and combining prayers, and is it permissible to delay all Nawafil until the end of the day due to an excuse?

Whoever combines two prayers (either by advancing the second prayer to the first prayer's time or delaying the first prayer to the second prayer's time) should begin with the Sunnah prayers performed before the obligatory prayers, then pray the two obligatory prayers consecutively, and then perform the Sunnah prayers that come after the obligatory prayers, in order.

If Dhuhr and Asr are combined: one should pray the four rak'ahs of the Sunnah prayer before Dhuhr, then Dhuhr, then Asr, then the Sunnah prayer after Dhuhr, and then the Sunnah prayer for Asr.

If Maghrib and Ishaa are combined: one should pray the two obligatory prayers, then the regular Sunnah prayer for Maghrib, then the regular Sunnah prayer for Ishaa.

Some scholars have permitted other ways of combining prayers.

As for delaying the regular Sunnah prayers past their time and praying them all at once, its ruling depends on the permissibility of making up missed regular Sunnah prayers. Whoever believes in making them up allows this, and whoever does not believe in making them up does not allow it.

And whoever is diligent in performing supererogatory prayers while at home will have their full reward recorded if they travel and are unable to perform them.