in my old uni, you got done for plagarism if you repeated content from your essays during the year and your exams and if you plagarised yourself across different years - which was harsh, they never caught me tho :p
Actually hate the way people say undergrads are spoon fed, they may be, but only cos they have been through exams every year of their lives (SATS and AS levels started in my year) which means they are less interested in the subject and more in 'how to pass the exam'. Lecturers often can't understand this but when you have been trained into passing-the-exam behaviour, rather than just being knowledgeable generally then you do all you can to get the most precise info possible with the least amount of effort.