Utility in Economics

In Economics, Utility refers the satisfaction, which people get from their consumption activities.
Imagine you bought a pair of shoes. The satisfaction you are getting from the shoes, that is utility. Each and every person has different test and preferences. So Utility should varies from person to person.
Utility can be measured in two ways- 1. Cardinal Utility and 2. Ordinal Utility. Cardinal Utility can be measured in a scale and Ordinal Utility can be measured on the basis of ranking. Imagine you bought two Shirts, among them, according to you, first shirt's utility is 100 utiles and second shirt's utility is 150 utiles. This is Cardinal utility. And as the second shirt's utility is more than first one, so the second shirt's rank will be 1 in respect of utility. This is Ordinal Utility.
Utility can decrease gradually over the time. The more shorter the time period, merginal utility decrease more first. Think why World Cup is organised in a gap of four years or why telecom operators give offer like ‘unlimited free night calling’. If World Cup will organised in every year, we will lose our interest on World Cup which means Marginal utility will decrease. This is a characteristic of Utility.