When the Consumer Consume a particular type of goods more number of times in a specific period of time and as the consumption of the goods increases there is less utility which is derived from an additional unit of the good consumed by a consumer.
The rate of utility diminishes over the time. shorter the time period, more quickly Marginal Utility diminishes.
The rate at which marginal utility diminishes depends on individual tastes , preferences, choices,beliefs.
Example: There was a customer who feels very hungry so he visits a Sweet shop and he purchased Some pieces of Sweets from there.As he consume first piece of sweet he derived extra utility and feels satisfaction , after consuming first he goes for second sweet and consumed it, the satisfaction level of second sweet will be less then the satisfaction gained from eating the first.If a third is eaten,the Satisfaction will be less.
