Does a slight elongation affect the shaddah, and what is its correct duration?

Tajwid is of two types: obligatory, which is giving the letters their due and their rights such that they emerge from their proper articulation points; and recommended, which is that which falls under the category of beautification, such as ghunnah (nasalization) and madd (lengthening). The latter does not invalidate the recitation. Its precise definition is to be referred to those with expertise and specialization, without exaggeration or excess. Scholars and imams have warned against excessive attention to the letters and their articulation from their exits, to the point of departing from moderation. Indeed, over-meticulousness, artificiality, and obsessive whispering in articulating letters are not from the Sunnah of the Prophet, peace be upon him.