Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions. Celebrating birthdays is an innovation. So, a Muslim should not spend his time and money in that. For more details, please read the Fatwa: 84957. As for holding esteem parties on the occasion of success of children, to encourage them or to express happiness following their success is permissible. On the other hand, celebrating the Walimah (wedding banquet) is Sunnah of the Prophet (Sallallahu Alaihi wa Sallam) who ordered a married person to offer a Walimah even with one sheep. However, wasting wealth with extravagance in a wedding party or any other party is forbidden. Allah Says (interpretation of meaning): {…and eat and drink but waste not by extravagance, certainly He (Allâh) likes not Al-Musrifûn (those who waste by extravagance)….}[7:31]. He also Says: {Verily, spendthrifts are brothers of the Shayatîn (devils), and the Shaitân (Devil Satan) is ever ungrateful to his Lord.}[17:27]. Know that if there is any conflict between the obligatory rights such as giving Zakah, settling immediate debts, etc., and holding such parties then it is compulsory to perform the obligatory acts and leave the parties. Allah knows best.