What is better when water is unavailable: delaying the prayer until its last time or performing tayammum and praying at the beginning of its time?

This answer summarizes two situations for delaying prayer until the end of its time: knowing that water is available or believing it highly probable that it is available. This is to ensure the condition of purification with water is met. Conversely, it is preferable to perform the prayer at the beginning of its time in three situations: knowing that water is not available, or believing it highly probable that it is not available, or being in doubt and not believing either case more probable.