sciNote business model is based on the number of teams you wish to have.
A team is usually a group of people working on the same projects or experiments and sharing the same repositories (e.g. protocol repository) as well as same database of samples.
Within an individual team you can invite unlimited number of users, therefore, you do not need to worry if a person leaves or joins a team.
To learn more about how to invite others to your team read the following FAQ.