Rent-seeking is any deliberate attempt to obtain rents, usually by political power, market power, influencing and using the law, or a combination of such means. Rent-seeking benefits no one, except the rent-seeker. It is a good idea to discourage rent-seeking, and some ideas about that are discussed below.
In the wonderful book The invisible hand? How market economies have emerged and declined since AD500, Bas van Bavel analyzes three examples of pre-industrial market economies: Iraq in the early Middle Ages, Italy in the high Middle Ages, and the Low Countries in the late Middle Ages and the early modern period. He analyzes that these societies thrived with dynamic and open markets, and how the growth of prosperity leads to the rise of new elites who accumulate assets, and how elites and privileged groups gradually tend to protect those assets, thus reducing dynamic and open markets. We can view this process as an increase in rent-seeking, which gradually leads to a decline of a society in the long run. With this in mind it is a good idea to pay attention to rent-seeking and to consider means to discourage it.
Rents 