Is supplicating without a reason not a Sunnah?

Supplication (Du'a) is religiously commanded, and its reasons are never exhausted. Even if a servant has worldly sufficiency, they still need to ask Allah for the continuation of blessings, for gratitude for them, and for their use in obedience, just as the Prophet Ayyub (peace be upon him) did. Humankind is in constant need of supplicating Allah and resorting to Him, even for the forgiveness of sins, for pardon, for entry into Paradise, and for salvation from Hellfire. Allah the Almighty says about His prophets: "Indeed, they used to hasten to good deeds and supplicate Us with hope and fear, and they were to Us humbly submissive" (21:90). As for supplicating for something already attained, there is no basis for it, and it is not part of the Sunnah (definition).