Demand is the willingness and ability to buy a good or service at a given price and time. It isn’t just wanting something; it requires both desire and purchasing power. In real estate, demand for housing increases with factors like rising incomes, population growth, and favorable financing, and it typically falls when prices rise or credit is tight. The concept is often shown as the inverse relationship between price and quantity demanded. The other terms don’t describe this need-to-buy concept: a comparable is a property used to estimate value, a buyer’s market describes conditions when supply exceeds demand, and diminishing returns is a production principle about output gains from additional input.

The state's authority to provide for the general welfare comes from police power, the broad ability to regulate private land use, behavior, and activities to protect health, safety, morals, and the welfare of the community. In land use, police power shows up through tools like zoning, building codes, and nuisance controls, all designed to promote orderly development and public protection. Zoning is a prime example of this power in action, since it sets allowed uses, densities, and standards to achieve welfare goals. Taxation, while essential for funding services, is a revenue-raising tool rather than the regulatory authority for general welfare. Eminent domain allows the government to condemn private property for public projects with compensation, but it’s a separate, more targeted power used to assemble land for specific public needs rather than the ongoing regulatory framework that protects welfare.

A judgment lien is created when a court orders a debtor to pay a creditor. That court order is recorded as a lien against the debtor’s real estate in the county where the property is located, so the property cannot be sold or refinanced without addressing the lien. It stays in place for a set period and can be renewed until the judgment is satisfied. This is different from tax liens, which come from unpaid government taxes; mortgage liens, which arise from a loan the borrower used to buy the property; and HOA liens, which come from unpaid homeowners association dues. The key idea is that a judgment lien originates from a court order to pay a creditor.

Diminishing returns describes the situation where the added value from an investment is smaller than its cost. In real estate, you might invest more money into improvements, but each additional dollar yields a smaller increase in value than the one before. Eventually, further spending can add little value or even reduce overall efficiency, so the value gained does not keep pace with the cost. External obsolescence refers to depreciation caused by factors outside the property, not the relationship between investment cost and value. Assemblage is the process of combining parcels to raise land value, often by creating a larger or more usable parcel. Capitalization is about converting net income into property value, not the diminishing return on investment.