For SimaPro Commercial plans (Expert, Power), the number of installations equals the number of users bought. For instance, if you have a single-user license, you can only install SimaPro on one machine at a time.
For the PhD plan, one installation is permitted per user license.
For the Education desktop edition, students and/or staff can install the single-user version multiple times as needed, provided it is used for educational purposes only and the usage is tied to one lecturer and their students.