What is the maximum users per license?

Licenses can be assigned as many times as you need, but can only be assigned to one user at a time. Thus, you can assign the license to User A on Monday, User B on Tuesday, etc. 

(Edited 8/28)
Since this post, Zoom has changed how often admins can re-assign licenses between users on their account. Unfortunately, I do not have any information that I can share regarding how many license re-assignments are allowed per day/week/month, so it is recommended that admins purchase additional licenses for their account to increase the limit of license assignments.