I have a medium with short handles and had a large with long handles [hated the color]. Long handles can be held, short cannot be on the shoulder. Medium holds a lot but not so many books, works as a toiletry bag though.
Leather can be washed. I have washed stinky old Coaches, a couple bent out of shape Dooneys and an ancient Ghurka that was even lined. Don't know if I am brave enough to put in the washing machine but hand washing is fine for many leathers.