What is the meaning of "O Ever-Living, O Self-Subsisting, by Your mercy I seek assistance, rectify all my affairs for me," and when is it recommended to supplicate with it?

The meaning of the aforementioned supplication is the believer's request to Allah Almighty and his invocation of Him by His names, The Ever-Living, The Self-Subsisting, and seeking help through His mercy to rectify all of his affairs, and that He not abandon him to himself for the blink of an eye. Al-Qayyum is the One Who subsists by Himself and sustains all others.