/ic/ - Artwork/Critique

Tried drawing hands for the first time. Is it a bad habit to find other features in the drawing to aid in measuring and determining what goes where?

For example the red line I noticed (on my arms at least) the outer line of arm sort of goes through the middle of your pointer finger.

I also used the outer line of the thumb and realized the inner line is parallel.

When I do gesture drawing I also find for stuff like this, like if the elbow is in line with the chin, if the left foot sort of matches up with the right ankle etc.