Time is irrecoverable and unstorable ()
The great diplomat Chanakya Pandita pointed out that one moment of time is more valuable than wealth equivalent to millions of gold coins, because the wealth, if lost, can be regained, whereas time, is lost, can never be regained; it is irrecoverably gone.
Time is not only irrecoverable, but also unstorable. We can choose whether to spend our wealth or not; we cannot choose whether to spend our time: with every passing moment, it is unavoidably spent. We cannot choose whether to spend time, we can only choose how to spend it.
Before choosing to take up any activity that involves a substantial amount of time, one way to ensure a wise choice is to ask this self-probing question: If someone would ask me to spend a substantial amount of money on this activity, would I be persuaded to do so? If not, then should I be persuaded by my mind to spend something even more valuable than money on this activity?