Is continuous phone communication between a husband and wife, one of whom is traveling, considered extravagance or obedience to Allah, knowing that they spend money on these calls?

Islam forbade extravagance and condemned it in the texts of the Quran and Sunnah (definition), as in the Almighty's saying: "And do not be extravagant; indeed, He does not like those who are extravagant," and His saying: "Indeed, the extravagant are brothers of the devils." A Muslim should be moderate, as Allah described the servants of the Most Merciful: "And those who, when they spend, are neither extravagant nor stingy, but a moderate way between these." Extravagance is spending something beyond necessity. Spending money on daily calls merely for communication or reassurance is considered extravagance in money and time, especially if prolonged. Therefore, one should be economical with money and time, spending them on what benefits in religion and worldly matters, and suffice with calls when needed, while taking advantage of free or discounted communication programs.