Why did thomas jefferson believe that the constitution should be amended every generation or so? need answer asap

Because he can incorporate the changing ideas of a generation. 

Thomas Jefferson considered the constitution to be a living document. He believed that the more we progressed in culture, the constitution would have to follow suit in order for our society to be more enlightened. He felt that as times change, rules may change and his train of thought is still practiced by many people today.

Starvation, debt, financial downfall.