The most fundamental constraint is limited time

Why in almost all societies have married women specialized in bearing and rearing children and in certain agricultural activities, whereas married men have done most of the fighting and market work?

Economy is the art of making the most of life.

Fines are preferable to imprisonment and other types of punishment because they are more efficient. With a fine, the punishment to offenders is also revenue to the State.

Human capital analysis starts with the assumption that individuals decide on their education, training, medical care, and other additions to knowledge and health by weighing the benefits and costs. Benefits include cultural and other non-monetary gains along with improvement in earnings and occupations, while costs usually depend mainly on the foregone value of the time spent on these investments.

A stronger yuan could lead to greater Chinese asset accumulation in the U.S. and elsewhere.

Different constraints are decisive for different situations, but the most fundamental constraint is limited time.