What are two reasons why laws need to be able to change?

examples would help.
thanks!
A. to a Politician. Well that's were the money is at.
B. To bring back us in a unpopular War and have fuel prices sore out of control. So when your constituents seize kicked in the (a)#$%$ You make Billions.
1) laws become prehistoric (obsolete) over time (dont know an example)
2) The words in an act can be interpreted in more than one way(people will try and be paid their way around laws by assuming a word/s in an achievement meant something else (Maddox V Storer)

Buzz me if you need a clearer explanation
technology
example: music industry, phone spying, camera phones