Goal (based on the contract): 20% of your weekly workload. In practice, it depends a lot on the course. It’s often a good idea to TA the same class multiple times, as it gets easier each time.

A common misguided attempt at reducing load is to try and do the minimum possible each semester. This doesn’t work because “the minimum” still includes a fair bit of work, plus some work to know the basics of the subject. Instead, find a course you like, ask the prof to choose you as a TA, and after the first 1-2 times it’ll be much easier for you to do work and the prof will be happy too since they get a motivated TA.

If you like teaching, TAing is a great opportunity to do that. Depending on the prof, you might be able to give a lecture during the semester, for instance.

Exemptions: first semester, last semester of the 4th year, last semester of 5th year (if an extension is obtained).

Pro tip: If you have an exemption, take it! There is no need to TA in your first semester, you will have plenty of time to do it afterwards.

Registration system with skills and preferences. It often happens that students from the lab TA their prof’s course.

French-speaking students are more likely to be assigned to bachelor-level classes taught in French. The way to get out of this is to have a prof specifically request you for their course.