I currently have 19 e-mail accounts set up in my mail app. Most accounts are for various businesses that I run because when I set them up, I always create an info@ account as the general account and then if needed a support@ account linked to my help desk software. Just counting the info@ type accounts, I have 17 for business, a personal e-mail account and finally a family e-mail account for anything related to my children, house, bills etc.
For years I have struggled to keep the total number of messages in those accounts below 70.