Normally you need to do right shoulder checks for right turns, but not left checks before left turns.
When you turn right, there are crosswalks and other areas where there may be bikes and pedestrians to the right of you, that may be hiding in your blind spot. Right shoulder checks are essential before turning right to ensure it is safe.
When you turn left, what’s in your left blind spot? Normally just the wrong side of the road, i.e. cars travelling in the opposite direction. Normally you can simply look out your driver’s side window and check the pedestrian area to your left before turning.
ICBC driver examiners do not require you to do left shoulder checks before turning left. Most experienced drivers do not do them either. But for sure you could do them if you feel it’s important.
You may decide to do a left shoulder check in certain cases when an intersection may be on a different angle or where you think there may be pedestrians in your blind spot.
*It never hurts to do a left shoulder check before turning. There have been collisions where one vehicle attempts a left turn at the same time as the vehicle behind it attempts to pass it. Can these types of collisions be prevented by more attentive mirror-checking, or is a left-shoulder check always essential? Personally I hardly ever do a left shoulder check before doing a left turn, and I hardly ever see other drivers do one either.I think that maintaining a 360 degree awareness of what’s going on around us at all times is one of the best ways to prevent those types (and other types) of collisions.