Nature of the Commodity
In the case of basic necessities of life, Ep. is less elastic while in case of luxurious goods, Ep is more elastic. In other words, a higher change in the price of necessity brings a small change in its Qd while a smaller change in the price of a luxurious good brings a big change in its Qd.
A Case of Substitutes
In case of the availability of the substitute for any commodity, Ep is more elastic e.g. a slight increase in the price of Coca Cola brings about a remarkable increase in demand for Pepsi.
A Case of Compliments
In the case of complementary goods, Ep is less elastic. For example, petrol is used as a complementary good in a car and a higher change in the price of petrol brings about a small change in the demand for a car.
Variety of Uses
If a commodity has its several uses, its demand is more elastic and vice versa. For example, there is a variety of use of milk, it is used in dairy products, bakery products, and homemade products etc. All it results in a big change in Qd of milk due to a smaller change in its price.
If one commodity is durable and it can be used for a long period, its demand is more elastic and vice versa. i.e. demand for the car.
High-priced commodities cannot be purchased by poor people and any change in the price of these commodities does not reflect a greater change in Qd by the poor people. Similarly, low-priced goods are not purchased by rich people and a change in the price of these goods does not show a remarkable change in Qd of these goods by rich people.
Demand for rich persons is less elastic because they are less sensitive to price change due to high income. Demand for poor persons is more elastic because they are more sensitive to price change due to low income.
If the use of a commodity is deferrable, its demand will be more elastic and vice versa.
Habits, Fashions & Customs
If a commodity becomes the part of the habit, fashion or custom its demand is perfectly inelastic. The people purchase such commodities at every cost.
Future expectations about the price also determine the elasticity of demand. If a higher price is expected by consumers in future, demand is more elastic and vice versa.
In the short run, demand is less elastic while in the long run, it is more elastic because new substitutes appear in the long run.