The first point you raised is 'time preference', which is simply the discounting we apply to future or uncertain income over immediate value.
The second one is 'marginal utility', which is perhaps best described as the difference in value of a litre of water to a dehydrated man in a desert vs. a man who owns a desalination plant.
The second one is 'marginal utility', which is perhaps best described as the difference in value of a litre of water to a dehydrated man in a desert vs. a man who owns a desalination plant.