As a teaching-assistant, how can I avoid repetitive teaching? As a teacher assistant, I am always thinking about preparing my students with up-to-dated teaching materials and examples; however, I can see many TAs in my department who teach the content they used to teach in the past semesters and now it is obvious that because the students have access to the previous year's pamphlets and handouts, they are not encouraged to attend these TAs classes. Even some of these students just copy and paste the problems and assignments from the past homeworks.


  As a teacher assistant, how can I avoid being stuck in repetitive
  teaching?


However, changing the problems each semester seems really a hard work and is almost impossible because the TA has to revise more than a hundred question or even find such quantity of new problems.


  What are the techniques you use to keep your teaching material up-to-dated and
  alluring to the interested student; also to avoid lazy student to copy
  the paste semester materials?




As asked in one of the comments,

The courses I do teaching assistantship is engineering mathematics for masters students consisting solution of partial differential equations and also ordinary differential equations for bachelors students of engineering or one or two other subjects related to my major; (each semester I may have only one of these classes, I don't take simultaneous teaching assistantship classes).

I have regular classes each week for instance having two hours a week teaching assistant class.

I usually prepare some problems and after a brief review on the methods, formulas and concept; I solve those problems for students. I usually photocopy my problems for my students. Also, at the end of each topic, I assign them some problems to solve and ask their questions if they have any. Also, I give them two exams, one at the middle of the term and one at the end of each term.
An answer looking at the bigger picture:

Stop teaching the same class all the time!

If you've taught the same class so often that you can reuse your material without thinking about it much, then it's time to branch out next semester and teach something else.  Teaching a variety of classes is more fun and rewarding (as they say, the best way to learn a subject is to teach it, so this way you learn more subjects).  It is valuable experience for an academic or teaching career, and showing a breadth of teaching experience can be helpful in a job search.

Maybe your department just keeps assigning you this course and you assume you have no choice.  Try just asking to be assigned something else - contact whoever is in charge of those assignments and ask what else might be available.  Of course you might not get what you want, since making teaching assignments is always complicated and requires many constraints to be satisfied, but there's a good chance of having your preferences at least taken into account.  If you don't get what you want this semester, you might have a better chance in a future semester as they try to make it up to you.