Is it permissible to pay for the sacrificial endowments (waqfiyat al-adahi), the breaking of the fast for the fasting person (ifṭār aṣ-ṣāʾim), and the sponsorship of orphans (kafālat al-aytām) all at once for one's entire life, fearing future inability to work? And is this act an obligation or a charity?

There is no specific time for feeding a fasting person and sponsoring orphans. Both are permissible at any time, and reward is attained for them. They are recommended, but may become obligatory through a vow or if they become incumbent upon a specific individual. As for the Udhiyah (sacrifice), it is only permissible during the days of Nahr (slaughter) after the Eid prayer. It is a confirmed Sunnah and becomes obligatory through a vow. Due diligence must be exercised when donating funds to charitable organizations to ensure they reach their rightful beneficiaries. It is permissible to allocate funds for Udhiyah annually, and its Sunnah status is not lifted from one who is capable of performing it due to the depletion of these funds.