The three-rak'ah form sets Maghrib apart and is treated in the manuals as a fixed peculiarity of the sunset prayer, not to be altered. Because sunset is a decisive and easily observed moment, Maghrib timing occasions less of the scholarly divergence that attaches to the afternoon prayer, though schools discuss precisely how long its window extends, some closing it with the disappearance of the evening twilight, others allowing it to run until the onset of the night prayer.
Maghrib forms a pair with the following Isha in the practice of combining prayers. Twelver Shia Muslims regularly pray Maghrib and Isha together after sunset, and Sunni law permits their combination for travellers and in cases of need such as rain or illness, so that the sunset and night obligations, like the two midday ones, are frequently kept in a single sitting.
A further and better-known difference concerns when Maghrib's time actually begins: Sunni practice generally holds the prayer permissible as soon as the sun's disc has fully set, while Twelver Shia jurisprudence typically requires waiting until the reddish glow in the eastern sky has faded as well, a stricter threshold that regularly places the Shia start time several minutes after the Sunni one and is among the clearest everyday timing differences between the two branches of Islamic practice.