* In theory; individuals seek to achieve fulfilment, happiness and/or satisfaction.
* In economic terms, they seek 'UTILITY'

* This includes buying goods and services we want (not necessarely the goods and services we need or are good for us)

* The answer is 'yes and no'. 'Utility' in itself is a very subjective (personal) concept, so we can't measure utility.
* BUT We can measure how much more utility we get by consuming an extra unit of a good or a service.

* We ask ourselves: 'how much more utility do I get if a get more of this good or a service?'

* The extra unit of utility you get by drinking a second glass is the 'Marginal Utility'.
* If you are very thirsty, a second drink would give you high levels of utlity too.

* At some point, however, you will have enough of that drink and will stop drinking.
* Do you experience the same amount of utility with every extra drink?

* This law asserts that the greater the amount of a service/good you counsume, the less utility you feel.
* In plain English: after a certain point, you don't feel like having more of a good or a service, so you stop.