Goods that are considered to be needs tend to be inelastic .
The microeconomic theory classifies the goods as elastic or inelastic, according to the variation that occurs in the demand before the percentage variations in the prices.
Elastic goods are the goods in which the demand varies greatly when the price increases or decreases. These goods are usually considered non-essential, or superfluous.
Inelastic goods are those goods in which even with a significant percentage change in prices, their demand does not vary significantly. This is because these goods are considered essential for consumers. For example medcines.